by Yongkang An,
Xunfan Liao,
Lie Chen,
Qian Xie,
Ming Zhang,
Bin Huang,
Zhihui Liao,
Hui Guo,
Ali Jazib,
Jihui Han,
Feng Liu,
Alex K.‐Y. Jen,
Yiwang Chen
Two novel A1‐A2 type polymer donors, PB24‐3TDC and PB68‐3TDC, with deep HOMO energy levels are proposed for non‐fullerene polymer solar cells. Slightly regulating the alkyl side‐chains causes a substantial difference in molecular stacking and photoluminescence emission energy loss, leading to broadly varied Voc and Jsc. The best efficiency of 10.3% was achieved based on PB24‐3TDC:ITIC‐Th.
Introducing electron‐withdrawing groups onto donor‐acceptor (D‐A) type conjugated materials is a commonly used method for lowering their highest occupied molecular orbital (HOMO) energy level to achieve higher open circuit voltage (Voc) in polymer solar cells (PSCs). However, this method is rather costly due to the tedious synthesis and low yield involved in preparing the target monomers. Here, a novel design concept of using two different acceptor units to construct acceptor1‐acceptor2 (A1‐A2) type polymers with a deep HOMO level is proposed. Two A1‐A2 type wide bandgap (WBG) polymers, PB24‐3TDC and PB68‐3TDC, were designed for PSCs. The developed polymers possess proper energy levels and complementary absorption with an efficient electron acceptor ITIC‐Th. More importantly, by slightly regulating the alkyl side‐chains, molecular stacking and photoluminescence (PL) emission energy loss of polymers can be alternated significantly. As a result, tuned Voc from 0.9 to 1.0 V and short‐circuit current (Jsc) from 9.4 to 17.0 mA cm−2 can be achieved. The device based on PB24‐3TDC:ITIC‐Th exhibits a higher power conversion efficiency (PCE) of 10.3% compared to PB68‐3TDC:ITIC‐Th based device with a PCE of 7.88%. These results show that the design concept of A1‐A2 type polymer donors have great potential for blending with non‐fullerene acceptors for achieving high performance PSCs.
by Harrison Ka Hin Lee,
Jérémy Barbé,
Simone M. P. Meroni,
Tian Du,
Chieh‐Ting Lin,
Adam Pockett,
Joel Troughton,
Sagar M. Jain,
Francesca De Rossi,
Jennifer Baker,
Matthew J. Carnie,
Martyn A. McLachlan,
Trystan M. Watson,
James R. Durrant,
Wing C. Tsoi
Perovskite photovoltaic (PPV) cells employing benchmark device architectures with an alternative hole transporting layer (HTL) are studied under simulated indoor environment. With a suitable combination of device architecture and HTL, a maximum power density of over 19 and 110 μW cm−2 under fluorescent lamps of 200 and 1000 lux are demonstrated, respectively. High potential of commercialization of a fully printable carbon‐based PPV architecture is suggested via demonstration of practical size module.
Indoor photovoltaics is one of the best sustainable and reliable energy source for low power consumption electronics such as the rapidly growing Internet of Things. Perovskite photovoltaic (PPV) cells with three benchmark device architectures – mesoporous PPV (mPPV) and inverted PPV (iPPV) with alternative hole transporting layers (HTLs), and carbon‐based PPV (cPPV) are studied under a simulated indoor environment. The mPPV cell using typical Spiro‐OMeTAD as the HTL shows the highest maximum power density (Pmax) of 19.9 μW cm−2 under 200 lux and 115.6 μW cm−2 under 1000 lux (without masking), which is among the best of the indoor PV. Interestingly, when PTAA is used as the HTL in the mPPV cell, the Pmax drops to almost zero under indoor light environment while its performance under one sun remains similar. On the other hand, when PEDOT:PSS is replaced by Poly‐TPD as HTL in the iPPV cell, the Pmax under indoor light improves significantly and is comparable to that of the best mPPV cell. This significant difference in indoor performance correlates well with their leakage current. The HTL‐free cPPV cell, prepared by fully up‐scalable techniques, shows a promising Pmax of 16.3 and 89.4 μW cm−2 under 200 and 1000 lux, respectively. A practical scale 5 × 5cm2 cPPV module is fabricated as a demonstration for real applications.
Author(s): Dong Ho Choi, Seong Kyung Nam, Kinam Jung, Jun Hyuk Moon
Abstract
Perovskite solar cells (PSCs) are currently exhibiting reproducible high efficiency; the manufacturing of low cost, scalable electron transport layers (ETLs) is becoming increasingly important. However, this remains a challenge for electron transport layers that exhibit excellent optical/electrical properties while being a thin film of simple morphology. Here we demonstrate the PSC of a 2D photonic crystal nanodisk (ND) array ETL that is compact, but greatly enhances light harvesting. The ND array is fabricated by nanosphere lithography using a monolayer of self-assembled polymer spheres as a physical mask. We fabricate ND arrays of various lattice constants simply by controlling the size of the polymer spheres. Optimal ND arrays exhibit strong forward scattering and optical confinement effects, greatly improving light harvesting in the perovskite layer. We also observe that the ND array improves charge transport by reducing contact resistance with the perovskite layer. ND array ETL PSCs reach 19% maximum power conversion efficiency, with low photocurrent-voltage hysteresis and stable photocurrent output.
Graphical abstract
We demonstrate a perovskite solar cell with a 2D photonic crystal as an electron transport layer and achieve a power conversion efficiency of up to 19% by the effect of improving light harvesting by photonic crystals.
Author(s): Xingyue Liu, Xianhua Tan, Zhiyong Liu, Haibo Ye, Bo Sun, Tielin Shi, Zirong Tang, Guanglan Liao
Abstract
All-inorganic CsPbBr3 perovskite solar cells (PSCs) have attracted tremendous attentions in the photovoltaic field these days in view of their outstanding stability, especially thermal stability. However, the bromide-rich perovskite, such as CsPbBr3, always suffer from a low phase-purity and poor morphology synthesized by traditional two-step deposition route. Herein, we demonstrate a facile multistep spin-coating strategy to fabricate high-quality CsPbBr3 films on the low-temperature processed compact TiO2 (c-TiO2) electron transport layer (ETL) of the carbon-based PSCs. As-prepared films exhibit more homogeneous with higher CsPbBr3-phase purity and larger average grain sizes up to 1 µm, compared to those prepared through traditional two-step deposition process. The champion power conversion efficiency (PCE) of the planar CsPbBr3 PSC is boosted from 7.05% to 8.12%, getting an increase by 15.2%, due to the increased crystallinity and light-harvesting ability as well as reduced trap states of the CsPbBr3 film. To further enhance the device performance, a SnO2 thin layer with much higher carrier mobility than TiO2 is introduced to passivate the c-TiO2 ETL. It is found that the SnO2 layer can not only improve the surface morphology of the ETL, but also reduce the current shunting pathways in the c-TiO2. The TiO2/SnO2 bilayered ETL possesses a superior electron extraction capability, beneficial to the charge transport and suppression of the interfacial trap-assisted recombination. The best-performing TiO2/SnO2-based CsPbBr3 PSC delivers an excellent fill factor of 0.817 and a high PCE of 8.79%, which is the highest efficiency for planar CsPbBr3 PSCs reported to date. More importantly, the unencapsulated all-inorganic PSCs show a promising humidity and thermal stability with no decline in efficiency when stored in ambient air at room temperature (25 °C) for over 1000 h and 60 °C for one month, respectively. Our work pave the ways for practical applications of cost-effective, highly efficient and stable all-inorganic PSCs.
Graphical abstract
Boosting the efficiency of carbon-based planar CsPbBr3 perovskite solar cells by a modified multistep spin-coating technique and interface engineering is demonstrated. A champion power conversion efficiency (PCE) of 8.79% is obtained for the as-prepared PSCs, which is the highest efficiency for planar CsPbBr3 PSCs reported yet.
Energy Environ. Sci., 2019, 12,929-937 DOI: 10.1039/C8EE02575D, Communication
Jiang Huang, Siheng Xiang, Junsheng Yu, Chang-Zhi Li Prismatic perovskite solar cells (Prim PVSC) were designed to mitigate thermodynamic losses of traditional single unit cells. By guiding the flow of light, the solar photons with high-to-low energy could be captured separately by the four subcells with varied, yet matched, bandgaps of MAPbIxBr3−x films. This is the first Prim PVSC with four series subcells that generates a record Voc of 5.3 V and a high PCE of 21.3%, providing a new method for breaking the PCE bottleneck of PVSCs. The content of this RSS Feed (c) The Royal Society of Chemistry
J. Mater. Chem. A, 2018, 6,24793-24804 DOI: 10.1039/C8TA07462C, Paper
Mengjie Sun, Chunjun Liang, Huimin Zhang, Chao Ji, Fulin Sun, Fangtian You, Xiping Jing, Zhiqun He A small fraction of DMSO additive in the second-step precursor is able to tune the intercalation and the nucleation, leading to a fine control of grain size and PbI2 residue and improved device efficiency. The content of this RSS Feed (c) The Royal Society of Chemistry
J. Mater. Chem. C, 2018, 6,13157-13161 DOI: 10.1039/C8TC05484C, Paper
Lingfeng Li, Peng Zhou, Jing Li, Yanping Mo, Wenchao Huang, Junyan Xiao, Wei Li, Zhiliang Ku, Jie Zhong, Yong Peng, Yi-Bing Cheng, Fuzhi Huang Cl-Incorporated triple-cation perovskite, as a novel absorber, has been developed to suppress hysteresis and enhance photoelectric performance. The content of this RSS Feed (c) The Royal Society of Chemistry
J. Mater. Chem. A, 2018, Accepted Manuscript DOI: 10.1039/C8TA09362H, Paper
Naveed Ur Rahman, Wasim Khan, Wenlang Li, Shaukat Khan, Javid Khan, Shizhao Zheng, Tongtong Su, Juan Zhao, Matthew Phillip Aldred, Zhenguo Chi Extending the spectral response from ultraviolet (UV) to the visible-light range and enhancing the UV-light stability are two remaining challenges for the development of perovskite solar cells (PSCs). Lanthanide complexes... The content of this RSS Feed (c) The Royal Society of Chemistry
J. Mater. Chem. A, 2018, 6,24805-24813 DOI: 10.1039/C8TA09868A, Paper
Gyujeong Jeong, Seungon Jung, Yunseong Choi, Junghyun Lee, Jihyung Seo, Dong Suk Kim, Hyesung Park Organic solar cells fabricated with Cu grid/graphene hybrid transparent electrodes exhibit both excellent device performance and long-term stability. The content of this RSS Feed (c) The Royal Society of Chemistry
Energy Environ. Sci., 2019, 12,157-163 DOI: 10.1039/C8EE02863J, Communication
Zhenye Li, Lei Ying, Peng Zhu, Wenkai Zhong, Ning Li, Feng Liu, Fei Huang, Yong Cao Advances in organic photovoltaic technologies have always been closely associated with a deeper understanding of bulk-heterojunction (BHJ) microstructure morphology, which is generally governed by the ink-formulation based on a single solvent or solvent mixtures. The content of this RSS Feed (c) The Royal Society of Chemistry
J. Mater. Chem. A, 2018, 6,24633-24640 DOI: 10.1039/C8TA08203K, Paper
Xiaomei Lian, Jiehuan Chen, Ruilin Fu, Tsz-Ki Lau, Yingzhu Zhang, Gang Wu, Xinhui Lu, Yanjun Fang, Deren Yang, Hongzheng Chen A merged annealing process based high quality 2D perovskite film and the corresponding PVSC with a PCE beyond 13%. The content of this RSS Feed (c) The Royal Society of Chemistry
J. Mater. Chem. A, 2018, 6,24580-24587 DOI: 10.1039/C8TA10015B, Paper
Sung Yun Son, Jae Won Kim, JooHyeon Lee, Guan-Woo Kim, Jisu Hong, Jin Young Kim, Taiho Park Random configuration approach simultaneously enhances charge mobility, solubility in a green solvent, and flexibility of a semiconducting polymer. The content of this RSS Feed (c) The Royal Society of Chemistry
Photo‐electrochemical water splitting is a promising route to low‐cost solar fuel generation. Recent advances for photocathodes and photoanodes are reviewed, with a particular focus on the durability of materials for water splitting. New emerging research directions within the field such as upgrading of biomass substrates and the use of organic photoabsorber materials are highlighted.
Abstract
Photo‐electrochemical (PEC) solar energy conversion offers the promise of low‐cost renewable fuel generation from abundant sunlight and water. In this Review, recent developments in photo‐electrochemical water splitting are discussed with respect to this promise. State‐of‐the‐art photo‐electrochemical device performance is put in context with the current understanding of the necessary requirements for cost‐effective solar hydrogen generation (in terms of solar‐to‐hydrogen conversion efficiency and system durability, in particular). Several important studies of photo‐electrochemical hydrogen generation at p‐type photocathodes are highlighted, mostly with protection layers (for enhanced durability), but also a few recent examples where protective layers are not needed. Recent work with the widely studied n‐type BiVO4 photoanode is detailed, which highlights the needs and necessities for the next big photoanode material yet to be discovered. The emerging new research direction of photo‐electrocatalytic upgrading of biomass substrates toward value‐added chemicals is then discussed, before closing with a commentary on how research on PEC materials remains a worthwhile endeavor.
by Joo‐Hyun Kim,
Charley Schaefer,
Tingxuan Ma,
Jingbo Zhao,
Johnathan Turner,
Masoud Ghasemi,
Iordania Constantinou,
Franky So,
He Yan,
Abay Gadisa,
Harald Ade
Linear correlation of fill factor and relative standard deviation of fullerene distribution reveals that a ternary blend morphology with a uniform and pure mixed amorphous domain is required to achieve efficient ternary solar cells. This is achieved by the right kinetic path, controlled by the material and process compatibility.
Abstract
Although ternary solar cells (TSCs) offer a cost‐effective prospect to expand the absorption bandwidth of organic solar cells, only few TSCs have succeeded in surpassing the performance of binary solar cells (BSCs) primarily due to the complicated morphology of the ternary blends. Here, the key factors that create and limit the morphology and performance of the TSCs are elucidated. The origin of morphology formation is explored and the role of kinetic factors is investigated. The results reveal that the morphology of TSC blends considered in this study are characterized with either a single length‐scale or two length‐scale features depending on the composition of the photoactive polymers in the blend. This asymmetric morphology development reveals that TSC blend morphology critically depends on material compatibility and polymer solubility. Most interestingly, the fill factor (FF) of TSCs is found to linearly correlate with the relative standard deviation of the fullerene distribution at small lengths. This is the first time that such a correlation has been shown for ternary systems. The criteria that uniform sized and highly pure amorphous domains are accomplished through the correct kinetic path to obtain a high FF for TSCs are specifically elucidated. The findings provide a critical insight for the precise design and processing of TSCs.
by Liuyang Zhou, Xuan He, Tsz-Ki Lau, Beibei Qiu, Tao Wang, Xinhui Lu, Beata Luszczynska, Jacek Ulanski, Shutao Xu, Guohui Chen, Jun Yuan, Zhi-Guo Zhang, Yongfang Li, Yingping Zou
Author(s): Hang Guo, Junqing Zhao, Qingshun Dong, Liduo Wang, Xueyan Ren, Song Liu, Chi Zhang, Guifang Dong
Abstract
Optoelectronic devices and self-powered technology can greatly contribute to the multifunctionality of information interaction. In this study, a self-powered organic optical communication system (SOCS) is demonstrated. The new system is composed of an organic light-emitting diode (OLED) driven by the triboelectric nanogenerators (TENGs) and a perovskite photodetector (PPD) supplied by the solar cell. Owing to the excellent performance of the optocoupler, the SOCS can effectively convert mechanical signals into light and then voltage signals, and synchronously, information transmission is achieved between two insulated units. With the SOCS, mechanical taping on different areas of the TENGs is encoded as binary to achieve a large amount of data transmission, and, a robotic hand is successfully controlled to complete different actions, which presents an intelligent application of SOCS in human-machine interaction. Moreover, the SOCS is capable of isolating the voltage difference of 2000 V between two isolated units and shows great adaptability in the extreme environment. This work not only greatly expands the application of TENGs and solar cells as power sources for self-powered electronics but also presents a new concept to achieve human-machine interaction.
Author(s): Jie Ding, Qiwei Han, Qian-Qing Ge, Ding-Jiang Xue, Jing-Yuan Ma, Bo-Ya Zhao, Yao-Xuan Chen, Jie Liu, David B. Mitzi, Jin-Song Hu
Context & Scale
Spin-coating/antisolvent techniques are widely used to deposit perovskite films for high-performance solar cells at laboratory scale. However, the spin-coating/antisolvent methods are not suitable for scalable device fabrication. Herein, we demonstrate an air-blading process to prepare entire perovskite solar cells without using any spin-coating/antisolvent steps and investigate the formation mechanism of high-quality perovskite film. High efficiencies of 20.08% and 19.12% were achieved for the fully air-bladed perovskite solar cells with illumination-exposure areas of 0.09 cm2 and 1.0 cm2, respectively, suggesting that the air-blading technique offers great opportunities for the practical fabrication of perovskite photovoltaics.
Summary
Perovskite photovoltaics has achieved rapid development largely due to the spin-coating technique with antisolvent steps at laboratory scale. However, the spin-coating/antisolvent technique limits the device dimension due to film uniformity issues. Up to now, it has been challenging to obtain perovskite devices with high efficiency (e.g., >20%) using scalable methods without antisolvent steps. Herein, an air-blading process is demonstrated to assemble the entire perovskite devices completely free from the spin-coating techniques. This method can coat perovskite precursor on substrates and simultaneously induce nucleation in perovskite intermediate films without any antisolvent steps, leading to highly uniform films. The fully air-bladed perovskite photovoltaics shows the best efficiency (reverse scanning) of >20% for 0.09 cm2 illumination-exposure area and the best efficiency of >19% for 1.0 cm2 illumination-exposure area with high reproducibility (stabilized efficiencies are 19.3% and 18.2%, respectively). Such an air-blading process offers a wide processing window for versatile high-performance perovskite optoelectronics toward large-scale production.
Energy Environ. Sci., 2019, 12,308-321 DOI: 10.1039/C8EE02730G, Paper
Yong Zhang, Seul-Gi Kim, Donghwa Lee, Hyunjung Shin, Nam-Gyu Park We report a novel approach for a fast phase transition of FAPbI3 at low-temperature and the effective removal of interfacial recombination in MAPbI3. The content of this RSS Feed (c) The Royal Society of Chemistry
by Yuanwei Wang,
Linda Varadi,
Adrian Trinchi,
Jianhua Shen,
Yihua Zhu,
Gang Wei,
Chunzhong Li
The coil–globule transition process with the assistance of high‐pressure spray is demonstrated to prepare scalable CsPbBr3@poly(methyl methacrylate) perovskite nanospheres, which are water‐resistant and highly fluorescent, allowing for live HeLa cell imaging.
Abstract
Despite their impressive optical properties, lead halide perovskite quantum dots (PQDs) have not realized their potential, especially in bioimaging applications, as they suffer from poor moisture and thermal stability, solvent incompatibility, and significant toxicity. Here, a spray‐assisted coil–globule transition method for encapsulating CsPbBr3 (CPB) PQDs into poly(methyl methacrylate) (PMMA) polymer nanospheres is reported. Polyvinylpyrrolidone‐capped CPB PQDs are synthesized via the ligand assisted reprecipitation method in dichloromethane. After dissolving PMMA, the above precursor solution is sprayed into petroleum ether under high pressure N2. High‐pressure nebulization restricts the interactions between PMMA polymer chains, resulting in the formation of ≈112 nm nanoscale composite spheres after a coil–globule transition. The CPB@PMMA nanospheres not only possess 73% quantum yields but retain 81% of fluorescence intensity after the exposure to water for over 80 days. Due to their confined size and biocompatible encapsulation, they are readily available for cellular uptake and exhibit no toxicity on live HeLa cells. Furthermore, the PMMA surface allows for functional surface modification, carrying the possibility of targeting specific biological species and processes.
Author(s): Qian Kang, Long Ye, Bowei Xu, Cunbin An, Samuel J. Stuard, Shaoqing Zhang, Huifeng Yao, Harald Ade, Jianhui Hou
Context & Scale
With the constantly enhanced photovoltaic efficiencies, as well as the advantages of low cost and light weight, organic solar cells (OSCs) exhibit a bright prospect for a new generation of renewable energy technology. For practical use, manufacturing large-area OSC devices by printing techniques is becoming critically important for the mass production of OSCs. However, the lack of printable cathode interlayer (CIL) materials has greatly impeded the pace toward practical production.
Here, we report an organic semiconductor possessing superior photoelectronic properties and good processablity, which is capable of serving as a printable CIL material. By using the printed CIL to make large-area devices, the highest photovoltaic efficiency for large-area OSCs was obtained, which paves the way for the commercialization and practical use of organic photovoltaics technology.
Summary
Currently, most cathode interlayer (CIL) materials for organic solar cells (OSCs) cannot be processed by printing techniques, which severely limits their use in practical productions. Herein, we report a naphthalene diimide (NDI)-based small-molecular compound (N,N-dimethylamino)propyl naphthalene diimide (NDI-N) as printable CIL for OSCs. NDI-N exhibits a unique advantage that combines the merits of high crystallinity and good film-forming property in one material, endowing the semiconductor with excellent electron-transport properties and good processability. By using the NDI-N as CIL, a high power-conversion efficiency (PCE) of 13.9% was achieved in a PBDB-T-2F:IT-4F-based OSC device. More importantly, a large-area OSC device of 1 cm2 was fabricated by using the blade-coated NDI-N CIL and an outstanding PCE of 13.2% was achieved, which represents the highest efficiency of large-area OSCs. The results in this work may pave the way for low-cost and mass production of OSCs.
J. Mater. Chem. A, 2018, 6,24693-24701 DOI: 10.1039/C8TA09164A, Communication
Yannan Zhang, Mengfan Gu, Ning Li, Yalong Xu, Xufeng Ling, Yongjie Wang, Sijie Zhou, Fangchao Li, Fan Yang, Kang Ji, Jianyu Yuan, Wanli Ma Among solution-processed photovoltaic materials, lead sulfide (PbS) colloidal quantum dots (QDs) possess a highly tunable bandgap and strong infrared absorption, while perovskites show extraordinary external quantum efficiency (EQE) in the visible region, which offers the opportunity to construct an ideal tandem cell of PbS QDs/perovskite. The content of this RSS Feed (c) The Royal Society of Chemistry
by Chenhui Jiang,
Rongfeng Tang,
Xiaomin Wang,
Huanxin Ju,
Guilin Chen,
Tao Chen
This research provides insightful investigation into the optical and electrical properties of alkali metals doped Sb2S3 films. The results show that Cs‐doping leads to the most efficient improvement in carrier concentration and film formability. The device delivers a power conversion efficiency of 6.56%, which is the highest efficiency in planar heterojunction Sb2S3 solar cells.
Sb2S3 as a stable light harvesting material has received increasing attention for solar cell applications. To improve the device efficiency, much effort has been put into the materials synthesis, interfacial engineering, and device structure design. Here, it is demonstrated that doping of alkali metal (Li, Na, K, Rb, Cs) ions essentially affects the morphological, crystal, optical and electrical properties of Sb2S3 films. The structural and compositional analysis shows that the doping is in form of alkali metal‐sulfur chemical bond at both surface and grain boundaries of Sb2S3 films. Compared with the pristine Sb2S3, we observe that Li and Na doping are not able to improve the device efficiency, while K, Rb, and Cs notably increase energy conversion efficiency. The most effective enhancement is found in Cs‐doped Sb2S3, where the carrier concentration, crystallinity, and film formability show remarkable improvement. The device based on the Cs‐Sb2S3 film delivers a power conversion efficiency of 6.56%, which is the highest efficiency in planar heterojunction Sb2S3 solar cells, regardless of whether the films are fabricated by a solution process or thermal deposition. This research identifies that doping of heavy alkali metals is an effective approach to improve the performance of Sb2S3 solar cells.
