Chen Weijie

The power conversion efficiencies (PCEs) of 16.75% and 16.76% are achieved in ternary layer-by-layer (LbL) and bulk-heterojunction (BHJ)-polymer solar cells (PSCs) with PM6, N3, and MF1 as active layers, respectively. Ternary strategy on PCE improvement can be confirmed from both LbL and BHJ-PSCs, which is primarily attributed to the optimized phase separation by incorporating appropriate MF1 as morphology regulator.

Abstract

Although the rapid development of polymer solar cells (PSCs) has been achieved, it is still a great challenge to explore efficient ways for improving power conversion efficiency (PCE) of PSCs from materials and device engineering. Ternary strategy has been confirmed as an efficient way to improve PCE of PSCs by employing three kinds of materials. In this work, one polymer donor PM6, and two non-fullerene materials N3 and MF1 are selected to prepare ternary PSCs with layer-by-layer (LbL) or bulk-heterojunction (BHJ) structure. The LbL and BHJ-PSCs exhibit PCEs of 16.75% and 16.76% with 15 wt% MF1 content in acceptors, corresponding to over 5% or 4% PCE improvement compared with N3-based binary PSCs with LbL or BHJ structure. The PCE improvement is mainly attributed to the fill factor enhancement from 73.29% to 76.95% for LbL-PSCs or from 74.13% to 77.51% for BHJ-PSCs by employing the ternary strategy. This work indicates that ternary strategy has great potential in preparing highly efficient LbL-PSCs via simultaneously optimizing molecular arrangement and the thickness of each layer.

Nature Materials, Published online: 29 November 2021; doi:10.1038/s41563-021-01178-x

A comparative analysis between steady-state and conventional performance testing of perovskite solar cells, single-junction and tandems, is presented to assess the limitations imposed by conventional current–voltage testing with a preset scan rate. Conditions for obtaining reliable results from conventional I–V curves are presented and further work proposed to help develop high throughput reliable performance testing for perovskite photovoltaics.

As perovskite photovoltaics (PV) advance from the laboratory to commercial prototypes, their accurate and reliable performance testing is becoming increasingly important. The well-documented dynamic response of perovskite solar cells to an external applied voltage has led to the development of steady-state performance measurement methods; however, these methods have not been widely adopted by the perovskite PV community. A key reason for this is that steady-state measurement methods take tens of minutes to complete, as opposed to conventional “fast” current–voltage (I–V) measurements usually lasting a few seconds. Fast I–Vs arise from a snapshot, almost always not a steady-state condition of the device; however, given their widespread use, the question arises: how do performance parameters of perovskite PV compare when measured with fast I–V and with a steady-state method? Results compiled from approximately 200 perovskite PV cells, including single junction, and two-terminal perovskite–perovskite and perovskite–Si tandems, show that fast I–Vs can provide a useful measure of the open-circuit voltage of the devices, while the short-circuit current and the overall efficiency can be widely misestimated. The implications of these findings on performance testing protocols are discussed and possible options for fast and accurate testing of perovskite PV are proposed.

Eight types of halide perovksites are trained through a generative machine learning approach for solar cells’ fabrication and the random forest model prediction of the bandgap and performance with the experimental results is validated.

Perovskites as semiconductors are of profound interest and arguably, the investigation on the distinctive perovskite composition is paramount to fabricate efficient devices and solar cells. The role of anion and cations and their impact on optoelectronic and photovoltaic properties is probed. A machine learning (ML) approach to predict the bandgap and power conversion efficiency (PCE) using eight different perovskites compositions is reported. The predicted solar cell parameters validate the experimental data. The adopted Random forest model presents a good match with high R ² scores of >0.99 and >0.82 for predicted absorption and J−V datasets, respectively, and show minimal error rates with a precise prediction of bandgap and PCEs. The results suggest that the ML technique is an innovative approach to aid the preparation of the perovskite and can accelerate the commercial aspects of perovskite solar cells without fabricating working devices and minimize the fabrication steps and save cost.

By inserting a functional polymer polymethyl methacrylate thin layer at the perovskite interface, the hole transfer layer (HTL)/Pb-free carbon-electrode-based Cs₂AgBiBr₆ perovskite solar cell achieves an enhanced power conversion efficiency of 2.25% with a high open-circuit voltage of 1.18 V owing to the reduced defects and suppressed short-circuit-induced shunt loss.

All-inorganic lead-free Cs₂AgBiBr₆ double perovskite solar cells (PSCs) have attracted growing attention owing to their eco-friendly features and robust intrinsic stability. However, arising from the rapid crystal growth, the poor film quality always leads to substantial non-radiative recombination and inferior performance improvement. Herein, high-efficiency and stable Cs₂AgBiBr₆ PSCs are obtained by introducing a functional polymethyl methacrylate (PMMA) layer at the perovskite surface to avoid direct contact between carbon and the underlying charge transfer layer, as well as to passivate the defects. When assembling into solar cells, the non-radiative charge recombination is suppressed and the interfacial charge extraction is accelerated. As a result, the carbon-electrode-based Cs₂AgBiBr₆ PSC yields an enhanced efficiency of 2.25% with a high open-circuit voltage of 1.18 V. Moreover, the unencapsulated device exhibits superior long-term stability owing to the protection of the PMMA layer from corrosion by the extraneous water and oxygen, retaining nearly 100% of the initial efficiency after storage in 25 °C, with 5% relative humidity (RH) for 80 days and high temperature of 85 °C, and 0% RH for 60 days, respectively. A simple method of polymer passivation for enhancing the performance and stability of Pb-free Cs₂AgBiBr₆ PSCs is provided.

2-Bromo-6-fluoronaphthalene (BFN) is employed to stabilize iodine ions in printable hole-conductor-free mesoscopic perovskite solar cells via the halogen bond interaction. Two halogen terminals and the fused ring help tune the energy levels of the perovskite. An efficiency of 16.77% is achieved due to accelerated hole extraction and inhibited charge recombination.

Perovskite solar cells (PSCs) are considered to be the most promising next-generation photovoltaic technology. Among all the configurations of PSCs, the printable hole-conductor-free mesoscopic PSC (p-MPSC) has unique advantages on low cost, large-area fabrication and fabulous stability, which endows it with the greatest potential for industrialization. The interfacial recombination losses, especially at the perovskite/carbon interface, are the bottleneck for further improving the power conversion efficiency (PCE) of p-MPSCs. 2-Bromo-6-fluoronaphthalene is introduced as an interfacial modulator for p-MPSCs through post-treatment. The bromo-terminal acts as an electrophilic site to interact with the iodine ion in perovskite via the noncovalent halogen bond. Meanwhile, the fused ring of naphthalene is capable to accommodate electron density that is attracted from the perovskite. This interaction induces a more favorable band structure at the interface. The hole extraction is promoted and the interfacial nonradiative recombination is inhibited. Accordingly, a champion p-MPSC with an improved PCE of 16.77% from 15.50% of the pristine device is obtained.

A simple structure non-fused-ring electron donor PF2 alternately consisting of furan-3-carboxylate and 2,2′-bithiophene presents very small synthetic complexity of 9.7% as well as low material cost of ≈19.0 $ g⁻¹. More importantly, PF2 delivers a high efficiency of 12.4% coupled with strong operational stability.

Abstract

Fused-ring electron donors boost the efficiency of organic solar cells (OSCs), but they suffer from high cost and low yield for their large synthetic complexity (SC > 30%). Herein, the authors develop a series of simple non-fused-ring electron donors, PF1 and PF2, which alternately consist of furan-3-carboxylate and 2,2′-bithiophene. Note that PF1 and PF2 present very small SC of 9.7% for their inexpensive raw materials, facile synthesis, and high synthetic yield. Compared to their all-thiophene-backbone counterpart PT-E, two new polymers feature larger conjugated plane, resulting in higher hole mobility for them, especially a value up to ≈10⁻⁴ cm² V⁻¹·s for PF2 with longer alkyl side chain. Meanwhile, PF1 and PF2 exhibit larger dielectric constant and deeper electronic energy level versus PT-E. Benefiting from the better physicochemical properties, the efficiencies of PF1- and PF2-based devices are improved by ≈16.7% and ≈71.3% relative to that PT-E-based devices, respectively. Furthermore, the optimized PF2-based devices with introducing PC₇₁BM as the third component deliver a higher efficiency of 12.40%. The work not only indicates that furan-3-carboxylate is a simple yet efficient building block for constructing non-fused-ring polymers but also provides a promising electron donor PF2 for the low-cost production of OSCs.

MXene (Ti₃C₂T _x ), a 2D material with high conductivity, mild reflectivity, flexible flake design, and configurable work function, is used as a novel type of back contact material in Sb₂(S,Se)₃ planar solar cells for the first time. Thus, a noble metal and/or hole transport layer-free antimony-based device with a high efficiency of 8.29% is presented.

Abstract

MXene, a class of 2D materials of metal carbide or nitride, has attracted a lot of attention recently due to its excellent optical and electrical properties. In this work, titanium-carbide MXene (Ti₃C₂T _x ) is introduced as a back electrode in Sb₂(S,Se)₃ thin-film solar cells (FTO/CdS/Sb₂(S,Se)₃/MXene) for the first time, which displaces traditional carbon (C) and gold (Au) electrodes entirely. Impressively, thanks to its high conductivity, mild reflectivity, and flexible flake architecture, the MXene-based device performance outperforms typical C and Au electrodes by 153% and 77%, respectively. Specifically, the tunable work function of MXene and a beneficial Sb–O bond formed between Sb₂(S,Se)₃ and MXene efficiently suppress the recombination and enhance charge transport by enjoying the unique merit of the rich terminal groups of MXene. As a result, the best efficiency of 8.29% of MXene-based Sb₂(S,Se)₃ solar device is achieved, which represents the highest performance of noble metal and/or hole transport layer-free derived Sb₂(S,Se)₃ solar cells to date. This result has revealed that MXene is a feasible material to substitute the back electrode in Sb-based solar cells to reach high efficiency, low cost, and high stability.

The buried interface between the perovskite and the electron transport layer is crucial for the further improvement of efficiency and stability of perovskite solar cells. Herein, the SnO₂/perovskite buried interface is enhanced by cesium modification. The CsI-SnO₂ complex facilitates growth of perovskite films and suppresses the carrier recombination. The champion efficiency of modified devices reaches 23.3% with excellent UV stability.

Abstract

The buried interface between the perovskite and the electron transport layer (ETL) plays a vital role for the further improvement of power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). However, it is challenging to efficiently optimize this interface as it is buried in the bottom of the perovskite film. Herein, a buried interface strengthening strategy for constructing efficient and stable PSCs by using CsI-SnO₂ complex as an ETL is reported. The CsI modification facilitates the growth of the perovskite film and effectively passivates the interfacial defects. Meanwhile, the gradient distribution of Cs⁺ contributes to a more suitable band alignment with the perovskite, and the incorporation of Cs⁺ into the perovskite at the bottom interface enhances the resistance against UV illumination. Eventually, a significantly improved PCE up to 23.3% and a much-enhanced UV stability of FAPbI₃-based PSCs are achieved. This work highlights the importance of cesium-enhanced interfaces and provides an effective approach for the simultaneous realization of highly efficient and UV-stable perovskite solar cells.

Here, blending polymers of different molecular weights as donors, to solve the conflict between coherence lengths and intermixed phase is proposed. This strategy fully utilizes the individual advantages of polymers of different molecular weights, which may reduce or eliminate trial-and-error approaches to match donor and accepter materials in regulating the microstructure of polymer/nonfullerene as acceptors solar cells.

Abstract

Long coherence lengths (CLs) of crystals and proper intermixed phase amount guarantee charge transport and exciton dissociate efficiently, which is crucial for organic solar cells (OSCs) to achieve high device performance. However, extending CLs usually reduces the intermixed phase, leading to an insufficient interface for exciton dissociation. Herein, a strategy using a binary polymer with different molecular weights as donor is employed, that is, poly(3-hexylthiophene-2,5-diyl) (P3HT) with high (P3HT-H) and low (P3HT-L) molecular weight are blended as donor, and (5Z,5′Z)-5,5′-(((4,4,9,9-tetraoctyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene-2,7-diyl)bis(benzo[c][1,2,5]thiadiazole-7,4-diyl))bis(methanylylidene))bis(3-ethyl-2-thioxothiazolidin-4-one) (O-IDTBR) is used as acceptor. In kinetics, the entanglements of P3HT-H are relieved due to the higher molecular diffusivity of P3HT-L. In thermodynamics, the miscibility of P3HT-L/O-IDTBR, P3HT-H/O-IDTBR, and P3HT-L/P3HT-H blends increases in turn. Hence, P3HT forms a more ordered structure with longer CLs after adding P3HT-L, which also drives O-IDTBR dispersed in P3HT crystalline regions diffuse to the O-IDTBR crystalline regions to further self-organize. Consequently, the CLs of both P3HT and O-IDTBR are extended, while keeping the intermixed phase amount proper. The optimized microstructure boosts device performance from 7.03% to 7.80%, which is one of the highest values reported for P3HT/O-IDTBR blends. This is a novel way to solve the conflict mentioned above, which may provide guidance to finely regulating the morphology of the active layer.

A rylene-fullerene hybrid, S-Fuller-PMI, is doped into PM6/Y6 blend film to construct ternary organic solar cells. The formation of dual-acceptor alloys gives rise to optimized phase separation morphology. The power conversion efficiency and fill factor of PM6:Y6:S-Fuller-PMI devices are significantly enhanced to 16.17% and 0.77, respectively. The enlarged entropy effectively boosts the long-term photothermal stability of ternary organic solar cells (OSCs).

Abstract

Molecular carbon imides, especially extended perylene diimides (PDIs) have been the best wide-band-gap nonfullerene acceptors. Despite their excellent photothermal/chemical stability, flexible reaction sites, and unique photoelectronic properties, there is still a lack of fundamental understanding of their molecular characteristics as a third component. Here, generations of PDIs with distinctive molecular architecture, are deliberately screened out as the third component to PM6:Y6. Only a rylene-fullerene hybrid, S-Fuller-PMI, surprisingly boosts the fill factor (FF) of ternary organic solar cells (OSCs) to 0.77 from 0.72 for PM6:Y6 binary ones, and therefore the power conversion efficiency (PCE) of ternary cells is enhanced from 15.3% to 16.2%. Compared with highly-flexible rylene dimer and rigid multimer, S-Fuller-PMI exhibits higher electron mobility, favorable surface tension, and, therefore tailored compatibility with Y6. These formed Y6:S-Fuller-PMI alloys play as a morphological controller to improve charge separation and transport process. Simultaneously, the suppressed photothermal-induced traps, along with inherent enlarged entropy effect, endow the ternary OSCs still with ≈70% of initial PCE even after 500 h continuous illumination, whereas only 53% is left in their binary counterparts. These results provide new insight into the molecular design principle for distinctive molecular carbon imides as the third component for efficient and durable PM6:Y6-based OSCs.

Controlling grain growth and passivating defects are essentially important for improving the photovoltaic performance of antimony selenide (Sb₂Se₃) thin-film solar cells. In this study, the seed-layer templated growth and post-air annealing is combined to prepare vertically oriented and passivated Sb₂Se₃ films on molybdenum substrates. As a result, substrate configuration Sb₂Se3 solar cells with a champion efficiency of 8.5% are demonstrated.

Abstract

Antimony selenide (Sb₂Se₃) is a promising low-cost photovoltaic material with a 1D crystal structure. The grain orientation and defect passivation play a critical role in determining the performance of polycrystalline Sb₂Se₃ thin-film solar cells. Here, a seed layer is introduced on a molybdenum (Mo) substrate to template the growth of a vertically oriented, columnar Sb₂Se₃ absorber layer by closed space sublimation. By controlling the grain orientation and compactness of the Sb₂Se₃ seeds, obtain high-quality Sb₂Se₃ absorber layers with passive Sb₂Se₃/Mo interfaces is obtained, which in turn improve the transport of photoexcited charge carriers through the absorber layer and its interfaces. Post-deposition annealing of absorber layers in ambient air is further utilized to passivate the defects in Sb₂Se₃ and enhance the quality of the front heterojunction. As a result of systematic processing optimization, Sb₂Se₃ planar heterojunction solar cells are fabricated in substrate configuration with a champion power conversion efficiency of 8.5%.

A series of polymer acceptors with controlled backbone regioregularities and side-chain structures is developed. All-polymer solar cells based on regioregular-C20 acceptor having a regioregular backbone and optimal side chain length achieve a high power conversion efficiency of 15.12%, attributed to high electron mobility and optimal blend morphology.

Abstract

Tuning the aggregation and crystalline properties of polymers is critical for realizing all-polymer solar cells (all-PSCs) with optimal blend morphology and high power conversion efficiency (PCE). In this study, a series of polymerized small-molecule acceptors (PSMAs) is developed to investigate important relationships among their crystalline/aggregation properties, the blend morphology, and the device performance of the resulting all-PSCs. A series of PSMAs (regiorandom (RRd)-C12, RRd-C20, RRd-C24, regioregular (RRg)-C20, and RRg-C24) with simultaneously-engineered i) side chain lengths of C12, C20, and C24, and ii) backbone regioregularities of RRd and RRg are synthesized to regulate their crystalline/aggregation properties. As a result, the highest PCE of 15.12% is obtained with all-PSCs based on RRg-C20 PSMA having regioregular backbone and optimal side chain length, attributed to high PSMA crystallinity and electron mobility as well as optimal blend morphology with a polymer donor. Thus, this study demonstrates the importance of simultaneous engineering of the backbone regioregularity and side-chain structures of PSMAs to enhance electron mobility, optimize blend morphology and, thus, achieve highly efficient all-PSCs.

Publication date: February 2022

Source: Nano Energy, Volume 92

Author(s): Fengyou Wang, Xin Li, Jinyue Du, Hui Duan, Haoyan Wang, Yue Gou, Lili Yang, Lin Fan, Jinghai Yang, Federico Rosei

In addition to the molecular design of the backbone, side chain engineering is another fundamental method for polymer modification. A benzo[1,2-b:4,5-b′]dithiophene (BDT)-benzodithiophene-4,8-dione copolymer PBDB-Cz is developed by employing carbazole as the conjugated side chain of BDT, which exhibits outstanding superior hole transport properties over its thiophene and alkoxy counterparts when used in n–i–p perovskite solar cells.

Abstract

In conventional n–i–p perovskite solar cells (PVSCs), electron donor (D)–acceptor (A) polymers have been found to be potential substitutes for doped spiro-based small molecule hole-transporting materials (HTMs) due to their excellent performance in hole mobility, film formability, and stability. Herein, a benzo[1,2-b:4,5-b′]dithiophene (BDT)-benzodithiophene-4,8-dione (BDD) copolymer PBDB-Cz is developed by employing carbazole as the conjugated side chain of BDT. PBDB-O and PBDB-T with alkoxy and thiophene as the side chain of BDT, respectively, are also synthesized and studied for comparison. The synergistic effect of the carbazole side chain and the BDT-BDD backbone to promote hole transport properties is found in PBDB-Cz. The carbazole side chain enhances both coplanarity and interaction of polymer chains, while simultaneously deepening energy levels and improving the hole mobility of the polymeric HTM. Consequently, PBDB-Cz outperforms two counterparts, exhibiting a promising power conversion efficiency (PCE) of 22.06%. Notably, the PBDB-Cz also improves the device stability, and the devices can retain more than 90% of their initial PCEs after being stored at ambient conditions for 100 days. To the best of the authors’ knowledge, this is the first report to incorporate carbazole into D–A polymeric HTM by side chain engineering.

A novel and low-cost phenothiazine-based self-assembly monolayer is designed and employed at the hole-transporting layer in a p-i-n perovskite solar cell, yielding a high efficiency over 22% along with an impressive operational stability over 100 h. This feature mainly originates from its well-aligned energy level match with the perovskite and efficient interfacial defect passivation.

Abstract

Recent advances in perovskite solar cells (PSCs) performance have been closely related to improved interfacial engineering and charge selective contacts. Here, a novel and cost-competitive phenothiazine based, self-assembled monolayer (SAM) as a hole-selective contact for p-i-n PSCs is introduced. The molecularly tailored SAM enables an energetically well-aligned interface with the perovskite absorber, with minimized nonradiative interfacial recombination loss, thus dramatically improving charge extraction/transport and device performance. The resulting PSCs exhibit a power conversion efficiency (PCE) of up to 22.44% (certified 21.81%) with an average fill factor close to 81%, which is among the highest efficiencies reported to date for p-i-n PSCs. The new SAM also demonstrates the outstanding operational stability of the PSC, with increasing PCE from 20.3% to 21.8% during continuous maximum power point tracking under a simulated 1 sun illumination for 100 h. The reported findings highlight the great potential of engineered SAMs for the fabrication of stable and high performing PSCs.

Crystallization engineering has played a key role in the development course of solution-processed Sn-based perovskite solar cells (PSCs). In this review, the state-of-the-art developments in crystallization dynamics control for Sn-based perovskites and their impact on the photovoltaic performance of PSCs are systematically summarized. It is hoped that this will promote the further development of Sn-based PSCs and many other optoelectronic applications.

Abstract

Tin-based perovskites show great potential in photovoltaic applications, and the development of the corresponding solar cells (PSCs) has made exciting progress during the past few years. However, owing to the high Lewis acidity and easy oxidation of Sn²⁺, Sn-based perovskite films suffer from fast crystallization and easy formation of vacancy defects with low activation energy during the solution film-forming process, resulting in poor film quality and inferior device performance. Therefore, an in-depth understanding and rational control of film-forming dynamics of Sn-based perovskites is essential to improve the photovoltaic performance of their PSCs. In this review, the state-of-the-art developments in crystallization dynamics control for Sn-based perovskites and their impact on the photovoltaic performance of PSCs are systematically summarized. The review begins with the introduction of fundamentals and key difficulties for the control of the crystallization process of Sn-based perovskites. Then, the advanced strategies that focus on regulating the crystallization process of Sn-based perovskite films are comprehensively reviewed, including solvent engineering, additive engineering, cation engineering, and film-forming technique engineering. Finally, future perspectives and research directions, regarding the smart control of crystallization dynamics of Sn-based perovskite film, are discussed towards high-performance and stable Sn-based PSCs.

New polymer acceptors (P_As) are developed by embedding flexible conjugation-break spacer (FCBS) units into the rigid backbones. The incorporation of FCBS affords effective modulation of the crystallinity and pre-aggregation of the P_A and attains optimal blend morphology. As a result, the all-polymer solar cells exhibit both a high efficiency of 14.68% and excellent mechanical robustness with a crack onset strain of 21.64%.

Abstract

High efficiency and mechanical robustness are both crucial for the practical applications of all-polymer solar cells (all-PSCs) in stretchable and wearable electronics. In this regard, a series of new polymer acceptors (P_As) is reported by incorporating a flexible conjugation-break spacer (FCBS) to achieve highly efficient and mechanically robust all-PSCs. Incorporation of FCBS affords the effective modulation of the crystallinity and pre-aggregation of the P_As, and achieves the optimal blend morphology with polymer donor (P_D), increasing both the photovoltaic and mechanical properties of all-PSCs. In particular, an all-PSC based on PYTS-0.3 P_A incorporated with 30% FCBS and PBDB-T P_D demonstrates a high power conversion efficiency (PCE) of 14.68% and excellent mechanical stretchability with a crack onset strain (COS) of 21.64% and toughness of 3.86 MJ m^-3, which is significantly superior to those of devices with the P_A without the FCBS (PYTS-0.0, PCE = 13.01%, and toughness = 2.70 MJ m^-3). To date, this COS is the highest value reported for PSCs with PCEs of over 8% without any insulating additives. These results reveal that the introduction of FCBS into the conjugated backbone is a highly feasible strategy to simultaneously improve the PCE and stretchability of PSCs.

Nature, Published online: 24 November 2021; doi:10.1038/s41586-021-03997-z

Incorporation of the pseudo-alkali metal cation dimethylammonium into the Cs-stabilized formamidinium lead triiodide perovskite precursor solution for fabricating the printed perovskite solar cells, achieves crystallization control and grain boundary passivation of the perovskite in the mesoscopic scaffold, yielding a device with a power conversion efficiency of 17.46% and long-term operational stability.

Upscaling efficient and stable perovskite materials is vital for metal halide perovskite solar cells (PSCs) and additive engineering contributes a lot to making high-quality PSCs. While the recent examples involved mixing dimethylammonium (DMA) cation has been employed for the fabrication of all-inorganic perovskites with improved efficiency and stability, the role of DMA cation in hybrid perovskite (formamidinium lead triiodide, denoted as FAPbI₃) remains inconclusive. Herein, DMA cations are substituted for FA sites of Cs_0.12FA_0.88PbI₃ for printable triple mesoscopic PSCs and shed lights on the roles and mechanism of DMA in the perovskite. It is found that a small amount of DMA is doped into the perovskite lattices, meanwhile, an intermediate compound DMAPbI₃ is formed and exists at grain boundaries, which improves the crystallinity of perovskite films and reduces nonradiative recombination through a passivation role. With these benefits, the best-performing printable PSC attained a power conversion efficiency of 17.46%. Unencapsulated devices maintained over 96% of the initial efficiencies in ambient condition for 960 h and 95% of the initial efficiencies after 360 h under continuous thermal aging at 85 °C in N₂ atmosphere.