shuhui

This paper presents aqueous, ultrasonically sprayed NiO_x hole transport layers (HTLs) with large‐area scalability and high photovoltaic performance in double cation perovskite solar cells, outperforming spin‐coated NiO_x from organic precursors and dramatically improving the fracture energy, a key metric of thermomechanical reliability. This robust and scalable HTL technology therefore has the potential to become a platform for scaling perovskite modules.

Abstract

Organometal halide perovskites have powerful intrinsic potential to drive next‐generation solar technology, but their insufficient thermomechanical reliability and unproven large‐area manufacturability limit competition with incumbent silicon photovoltaics. This work addresses these limitations by leveraging large‐area processing and robust inorganic hole transport layers (HTLs). Inverted perovskite solar cells utilizing NiO_x HTLs deposited by rapid aqueous spray‐coating that outperform spin‐coated NiO_x and lead to a 5× improvement in the fracture energy (G _c), a primary metric of thermomechanical stability, are presented. The morphology, chemical composition, and optoelectronic properties of the NiO_x films are characterized to understand and optimize compatibility with an archetypal double cation perovskite, Cs_.17FA_.83Pb(Br_.17I_.83)₃. Perovskite solar cells with sprayed NiO_x show higher photovoltaic performance, exhibiting up to 82% fill factor and 17.7% power conversion efficiency (PCE)—the highest PCE reported for inverted cell with scalable charge transport layers—as well as excellent stability under full illumination and after 4000 h aging in inert conditions at room temperature. By utilizing open‐air techniques and aqueous precursors, this combination of robust materials and low‐cost processing provides a platform for scaling perovskite modules with long‐term reliability.

In this work, organic ternary solar cells based on a model system comprising the polymers PDCBT and PTB7‐Th and PC₇₀BM are presented as electron accepting units. The photophysics of this blend is governed by a fast energy transfer process from PDCBT to PTB7‐Th allowed by a favorable molecular affinity between PDCBT and PTB7‐Th.

Abstract

Ternary blends with broad spectral absorption have the potential to increase charge generation in organic solar cells but feature additional complexity due to limited intermixing and electronic mismatch. Here, a model system comprising the polymers poly[5,5‐bis(2‐butyloctyl)‐(2,2‐bithiophene)‐4,4‐dicarboxylate‐alt‐5,5‐2,2‐bithiophene] (PDCBT) and PTB7‐Th and PC₇₀BM as an electron accepting unit is presented. The power conversion efficiency (PCE) of the ternary system clearly surpasses the performance of either of the binary systems. The photophysics is governed by a fast energy transfer process from PDCBT to PTB7‐Th, followed by electron transfer at the PTB7‐Th:fullerene interface. The morphological motif in the ternary blend is characterized by polymer fibers. Based on a combination of photophysical analysis, GIWAXS measurements and calculation of the intermolecular parameter, the latter indicating a very favorable molecular affinity between PDCBT and PTB7‐Th, it is proposed that an efficient charge generation mechanism is possible because PTB7‐Th predominantly orients around PDCBT filaments, allowing energy to be effectively relayed from PDCBT to PTB7‐Th. Fullerene can be replaced by a nonfullerene acceptor without sacrifices in charge generation, achieving a PCE above 11%. These results support the idea that thermodynamic mixing and energetics of the polymer–polymer interface are critical design parameter for realizing highly efficient ternary solar cells with variable electron acceptors.

Recent progress in antimony chalcogenide‐based photovoltaic materials and devices including Sb₂S₃ solar cells, Sb₂Se₃ solar cells, and Sb₂(S _x Se_1−x)₃ solar cells is comprehensively reviewed. The fundamental properties and preparation techniques of antimony chalcogenides are discussed. The achievements and challenges in antimony chalcogenide solar cells are highlighted. In addition, the outlook for future research in this field is provided.

Antimony chalcogenides such as Sb₂S₃, Sb₂Se₃, and Sb₂(S_xSe_1−x)₃ have emerged as very promising alternative solar absorber materials due to their high stability, abundant elemental storage, nontoxicity, low‐cost, suitable tunable bandgap, and high absorption coefficient. Remarkable achievements have been made in antimony chalcogenide solar cells in the past few decades, with the power conversion efficiency (PCE) currently reaching 9.2%, which is close to the PCE level required for industrial applications. To facilitate the realization of highly efficient antimony chalcogenide solar cells in the future, a comprehensive review of antimony chalcogenide‐based materials and photovoltaic devices is presented. First, the fundamental physical properties and preparation methods of antimony chalcogenide‐based materials are outlined, and then, notable recent developments in antimony chalcogenide‐based photovoltaic devices with various architectures are highlighted. Finally, the most prominent limitations are described, and approaches to achieving remarkable advances in antimony chalcogenide solar cells in the future are provided.

All‐polymer solar cells (all‐PSCs) fabricated via slot‐die printing are obtained. In situ grazing incidence wide‐angle X‐ray scattering reveals the multiple crystallization kinetics during film drying. Printing with 1,8‐diiodooctane leads to the formation of a multi‐length‐scale phase separation and eventually improves the solar cell efficiency up to 9.10%, which is the highest efficiency for printed all‐PSCs.

Herein, high‐performance printed all‐polymer solar cells (all‐PSCs) based on a bulk‐heterojunction (BHJ) blend film are demonstrated using PTzBI as the donor and N2200 as the acceptor. A slot‐die process is used to prepare the BHJ blend, which is a cost‐effective, high‐throughput approach to achieve large‐area photovoltaic devices. The real‐time crystallization of polymers in the film drying process is investigated by in situ grazing incidence wide‐angle X‐ray scattering characterization. Printing is found to significantly improve the crystallinity of the polymer blend in comparison with spin coating. Moreover, printing with 1,8‐diiodooctane as the solvent additive enhances the polymer aggregation and crystallization during solvent evaporation, eventually leading to multi‐length‐scale phase separation, with PTzBI‐rich domains in‐between the N2200 crystalline fibers. This unique morphology achieved by printing fabrication results in an impressively high power conversion efficiency of 9.10%, which is the highest efficiency reported for printed all‐PSCs. These findings provide important guidelines for controlling film drying dynamics for processing all‐PSCs.

Replacing the acceptors of 3,9‐bis(2‐methylene‐(3‐(1,1‐dicyanomethylene)‐indanone)‐ 5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2, 3‐d:2’,3’‐d’]‐s‐indaceno[1,2‐b:5,6‐b’]‐dithiophene (ITIC) and another fuse ring acceptor with withdrawing units of 1,1‐dicyanomethylene‐3‐indanone and hexyl side chains (IDIC) with rhodanine‐benzothiadiazole‐coupled indacenodithiophene with branched 2‐ethylhexyl side chains (EH‐IDT) in nonfullerene organic solar cells can not only enhance power conversion efficiency but also extend device longevity under light. Good miscibility between the donor and the acceptor is found to be a key factor in stabilizing the film morphology of the active layer and contributes to an excellent photostability.

Nonfullerene organic solar cells (OSCs) have achieved an impressive power conversion efficiency (PCE) over the past few years, showing a great potential for real applications. However, the study on the photostability and degradation mechanism of nonfullerene OSCs is far behind than that of fullerene‐based solar cells, which is crucial for the commercial applications of the technology. Herein, an efficient and stable nonfullerene OSC based on PCE10:rhodanine‐benzothiadiazole‐coupled indacenodithiophene with branched 2‐ethylhexyl side chains (EH‐IDT) is fabricated from environmentally benign solvent. The PCE10:EH‐IDT solar cell shows a high PCE of 9.17% and a long operational lifetime (T ₈₀) of 2132 h, compared with other two OSCs based on 3,9‐bis(2‐methylene‐(3‐(1,1‐dicyanomethylene)‐indanone)‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐d:2’,3’‐d’]‐s‐indaceno[1,2‐b:5,6‐b’]‐dithiophene (ITIC) and another fuse ring acceptor with withdrawing units of 1,1‐dicyanomethylene‐3‐indanone and hexyl side chains (IDIC) nonfullerene acceptors, with tested lifetimes of only 221 and 558 h, respectively. As indicated by the Flory–Huggins interaction parameters, ITIC and IDIC have poor miscibility with PCE10, which leads to morphology degradation, suppressed charge generation, increased trap states, and charge recombination in the photoaging test, which accounts for the significant loss of short‐circuit current density and fill factor during operation. The improved miscibility of the donor and the acceptor results in a more stable morphology, and the PCE10:EH‐IDT solar cells thus achieve an outstanding overall performance that combines high efficiency and superior photostability and paves the way for the potential practical applications of OSCs.

Thick‐film‐induced absorption compensation at short‐wavelength band is designed based on organic donors and acceptors with comparable bandgaps of 1.61 eV and suitable energy offsets for both the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), giving high J _sc and V _oc close to perovskite solar cells. As a result, a suppressed trade‐off between J _sc and V _oc among OSCs is demonstrated.

Herein, a high‐mobility polymer (Si25) pairing a nonfullerene acceptor (O‐IDTBR) is introduced to construct active layers of organic solar cells (OSCs). The OSCs based on Si25 and O‐IDTBR with comparable bandgaps of 1.61 eV show high open‐circuit voltage (V _oc) of 1.03 V. Suitable energy level offsets between the donor and acceptor as well as sufficient photon absorbance by a 400 nm thick active layer afford a notable short‐circuit current (J _sc) of 21.11 mA cm⁻², indicating a significantly suppressed trade‐off between J _sc and V _oc among OSCs. In addition, notable high power conversion efficiency (PCE) between 10.2% and 11.54% can be achieved with thick blend films from 210 to 560 nm, a thickness range beneficial to pin‐hole free printing. The maximum PCE of 11.54% corresponds to a 400 nm thick blend film, which is a rare thickness for high‐efficiency nonfullerene‐based OSCs. The corresponding fill factors (FFs) are between 51.59% and 53.33%. The inferior FF is due to a very low electron–hole mobility ratio, offering space for future FF elevation. The results highlight the high V _oc and J _sc potentials for thick‐film nonfullerene OSCs based on a high hole mobility donor as well as looking forward to a high electron mobility nonfullerene acceptor.

A 248 nm KrF excimer laser with high photon energy and low thermal effect is employed to perform a rapid surface modification on CH₃NH₃PbI₃ films for the first time. This approach can reduce the surface trap density of CH₃NH₃PbI₃ films effectively and improve the cell performance of perovskite solar cells obviously.

For perovskite solar cells (PSCs), the surface traps of perovskite films have great influence on the charge carrier behavior at the interface of perovskite and charge transport layers. In this investigation, a 248 nm KrF excimer laser with high photon energy and shallow penetration depth is introduced to perform surface modification on the CH₃NH₃PbI₃ film through irradiation for reducing its surface trap density for the first time. A whole excimer laser surface modification (ELSM) process can be completed in few seconds, and the actual interaction time of the excimer laser and perovskite film is only several hundred nanoseconds. After ELSM, the trap density of the CH₃NH₃PbI₃ film decreases from 1.61 × 10¹⁶ cm⁻³ to 5.81 × 10¹⁵ cm⁻³, and the nonradiative recombination is suppressed effectively. As a result, the open‐circuit voltage and the power conversion efficiency (PCE) of CH₃NH₃PbI₃‐based PSCs increase from 1082 ± 27 to 1117 ± 16 mV and from 16.69% ± 0.77% to 18.50% ± 0.65%, respectively, and the PCE of the champion device reaches 19.38%. In addition, the measured larger charge recombination resistance, slower open‐circuit photovoltage decay, and longer charge recombination lifetime confirm the effective suppression effect of ELSM on the charge carrier recombination in PSCs.

By introducing a CsPbBr₃ cluster into a triple cation perovskite film to form an inorganic perovskite‐passivated hybrid perovskite film, ion migration is largely inhibited and defect states are greatly passivated. The open‐circuit voltage of passivated solar cells increases from 1.15 to 1.195 V. More importantly, the T ₉₀ operational stability under light soaking of the device is significantly improved to 500 h.

Abstract

Ion migration and phase segregation, in mixed‐cation/anion perovskite materials, raises a bottleneck for its stability improvement in solar cells operation. Here, the synergetic effect of electric field and illumination on the phase segregation of Cs_0.05FA_0.80MA_0.15Pb(I_0.85Br_0.15)₃ (CsFAMA) perovskite is demonstrated. CsFAMA perovskite with a CsPbBr₃‐clusters passivated structure is realized, in which CsPbBr₃‐clusters are located at the surface/interface of CsFAMA grains. This structure is realized by introducing a CsPbBr₃ colloidal solution into the CsFAMA precursor. It is found that CsPbBr₃ passivation greatly suppresses phase segregation in CsFAMA perovskite. The resultant passivated CsFAMA also exhibits a longer photoluminescence lifetime due to reduced defect state densities, produces highly efficient TiO₂‐based planar solar cells with 20.6% power conversion efficiency and 1.195 V open‐circuit voltage. The optimized devices do not suffer from a fast burn‐in degradation and retain 90% of their initial performance at maximum power under one‐sun illumination at 25 °C (65 °C) exceeding 500 h (100 h) of continuous operation. This result represents the most stable output among CsFAMA solar cells in a planar structure with Spiro‐OMeTAD.

Layered 2D perovskite solar cells often suffer from poor carrier transport. Herein, the authors propose a homo‐tandem structure to extract the photogenerated carriers efficiently while retaining the optical density of the absorbers. It thus improves the power conversion efficiency of resultant devices by 30% without the penalty of moisture stability.

Layered two dimensional (layered 2D) organic–inorganic metal halide perovskites have attracted tremendous interest in photovoltaics due to its acceptable materials stability, especially the moisture resistance, when compared with their three dimensional counterparts. However, the limited carrier transport capability, which originates from the insulativity of bulky organic molecules, has significantly affected the resultant device efficiency. To create a shorter carrier pathway with sufficient optical density, the homo‐tandem device structure by using layered 2D perovskite absorbers is proposed. Following this strategy, the semi‐transparent device and filter bottom cells have been investigated and optimized using the same layered 2D perovskite absorber (BA₂MA₃Pb₄I₁₃). The corresponding four‐terminal tandem device is successfully demonstrated with the champion power conversion efficiency of 14.42%, which is 30% higher than that of single BA₂MA₃Pb₄I₁₃ perovskite devices (11.02%). A stabilized efficiency of 13.57% in the optimized champion tandem device also have been achieved. These results suggest alternatives to develop layered 2D perovskite based solar cells and other optoelectronic devices.

A specific bidentate molecule, 2‐mercaptopyridine, is demonstrated to substantially enhance anchoring strength at surface of metal halide perovskites, which improves the passivation efficacy and stability synchronously relative to monodentate counterparts. The highly stable bidentate anchoring based passivation on CH₃NH₃PbI₃ not only advances power conversion efficiency from 18.35% to 20.28%, but also leads to a champion lifetime in humid air.

Abstract

Chemical passivation is an effective approach to suppress the grain surface dominated charge recombination in perovskite solar cells (PSCs). However, the passivation effect is usually labile on perovskite crystal surface since most passivating agents are weakly anchored. Here, the use of a bidentate molecule, 2‐mercaptopyridine (2‐MP), to increase anchoring strength for improving the passivation efficacy and stability synchronously is demonstrated. Compared to monodentate counterparts of pyridine and p‐toluenethiol, 2‐MP passivation on CH₃NH₃PbI₃ film results in twofold improvement of photoluminescence lifetime and remarkably enhanced tolerance to chlorobenzene washing and vacuum heating, which improve the power conversion efficiency of n–i–p planar structured PSCs from 18.35% to 20.28%, with open‐circuit voltage approaching 1.18 V. Moreover, the CH₃NH₃PbI₃ films passivated with 2‐MP exhibit unprecedented humid‐stability that they can be exposed to saturated humidity for at least 5 h, mainly due to the passivation induced surface deactivation, which renders the unencapsulated devices retaining 93% of the initial efficiency after 60 days aging in air with relative humidity of 60–70%.

A linear hole‐transporting material (HTM) based on 9,9‐dihexyl‐9H‐fluorene and N,N‐di‐p‐methylthiophenylamine (denoted as FMT) is synthesized. The p‐i‐n perovskite solar cells (pp‐PSCs) with the indium‐doped tin oxide (ITO)/FMT/CH₃NH₃PbI₃ (MAPbI₃)/PCBM/Al structure shows a high power conversion efficiency (PCE) of 19.06%. Hence, FMT is one of the simplest HTMs applied in pp‐PSCs, which shows a PCE of over 19% without dopants.

Abstract

For commercial applications, it is a challenge to find suitable and low‐cost hole‐transporting material (HTM) in perovskite solar cells (PSCs), where high efficiency spiro‐OMeTAD and PTAA are expensive. A HTM based on 9,9‐dihexyl‐9H‐fluorene and N,N‐di‐p‐methylthiophenylamine (denoted as FMT) is designed and synthesized. High‐yield FMT with a linear structure is synthesized in two steps. The dopant‐free FMT‐based planar p‐i‐n perovskite solar cells (pp‐PSCs) exhibit a high power conversion efficiency (PCE) of 19.06%, which is among the highest PCEs reported for the pp‐PSCs based on organic HTM. For comparison, a PEDOT:PSS HTM‐based pp‐PSC is fabricated under the same conditions, and its PCE is found to be 13.9%.

High‐quality, pinhole‐free CH₃NH₃SnI₃ films are achieved from pristine NH₂NH₃SnI₃ perovskite, and the oxidation of Sn²⁺ to Sn⁴⁺ can be efficiently suppressed owing to the reduction agent hydrazine generated inside the films in the conversion. With the CH₃NH₃SnI₃ film as light absorber, mesoporous MASnI₃ perovskite solar cells were fabricated with a maximum PCE of 7.13 %.

Abstract

Tin‐based halide perovskite materials have been successfully employed in lead‐free perovskite solar cells, but the overall power conversion efficiencies (PCEs) have been limited by the high carrier concentration from the facile oxidation of Sn²⁺ to Sn⁴⁺. Now a chemical route is developed for fabrication of high‐quality methylammonium tin iodide perovskite (MASnI₃) films: hydrazinium tin iodide (HASnI₃) perovskite film is first solution‐deposited using presursors hydrazinium iodide (HAI) and tin iodide (SnI₂), and then transformed into MASnI₃ via a cation displacement approach. With the two‐step process, a dense and uniform MASnI₃ film is obtained with large grain sizes and high crystallization. Detrimental oxidation is suppressed by the hydrazine released from the film during the transformation. With the MASnI₃ as light harvester, mesoporous perovskite solar cells were prepared, and a maximum power conversion efficiency (PCE) of 7.13 % is delivered with good reproducibility.

Publication date: June 2019

Source: Nano Energy, Volume 60

Author(s): Long Zhou, Xing Guo, Zhenhua Lin, Jing Ma, Jie Su, Zhaosheng Hu, Chunfu Zhang, Shengzhong (Frank) Liu, Jingjing Chang, Yue Hao

Graphical abstract

Low temperature processed high performance all-inorganic perovskite solar cells with MoO₃ as interfacial layer have been achieved with PCE exceeding 14% via sequential graded thermal annealing process. Moreover, the unencapsulated device exhibited enhanced operational stability under continuously simulated sunlight illumination, thermal stability and outstanding air stability after 60 days of storage under N₂ condition.

A linear hole‐transporting material (HTM) based on 9,9‐dihexyl‐9H‐fluorene and N,N‐di‐p‐methylthiophenylamine (denoted as FMT) is synthesized. The p‐i‐n perovskite solar cells (pp‐PSCs) with the indium‐doped tin oxide (ITO)/FMT/CH₃NH₃PbI₃ (MAPbI₃)/PCBM/Al structure shows a high power conversion efficiency (PCE) of 19.06%. Hence, FMT is one of the simplest HTMs applied in pp‐PSCs, which shows a PCE of over 19% without dopants.

Abstract

For commercial applications, it is a challenge to find suitable and low‐cost hole‐transporting material (HTM) in perovskite solar cells (PSCs), where high efficiency spiro‐OMeTAD and PTAA are expensive. A HTM based on 9,9‐dihexyl‐9H‐fluorene and N,N‐di‐p‐methylthiophenylamine (denoted as FMT) is designed and synthesized. High‐yield FMT with a linear structure is synthesized in two steps. The dopant‐free FMT‐based planar p‐i‐n perovskite solar cells (pp‐PSCs) exhibit a high power conversion efficiency (PCE) of 19.06%, which is among the highest PCEs reported for the pp‐PSCs based on organic HTM. For comparison, a PEDOT:PSS HTM‐based pp‐PSC is fabricated under the same conditions, and its PCE is found to be 13.9%.

A novel approach to stabilize α‐CsPbI₃ perovskite through strain engineering, whereby CsPbI₃ perovskite is confined by a vertically aligned nanoporous template, is developed. By imposing a strain on the perovskite lattice, the ultrastable black α‐CsPbI₃ with its desirable optoelectrical properties is obtained. The density functional theory calculations on the formation energy confirm that the strain‐mediated phase stabilization is thermodynamically allowed.

Abstract

All‐inorganic cesium lead triiodide (CsPbI₃) perovskite is considered a promising solution‐processable semiconductor for highly stable optoelectronic and photovoltaic applications. However, despite its excellent optoelectronic properties, the phase instability of CsPbI₃ poses a critical hurdle for practical application. In this study, a novel stain‐mediated phase stabilization strategy is demonstrated to significantly enhance the phase stability of cubic α‐phase CsPbI₃. Careful control of the degree of spatial confinement induced by anodized aluminum oxide (AAO) templates with varying pore sizes leads to effective manipulation of the phase stability of α‐CsPbI₃. The Williamson–Hall method in conjunction with density functional theory calculations clearly confirms that the strain imposed on the perovskite lattice when confined in vertically aligned nanopores can alter the formation energy of the system, stabilizing α‐CsPbI₃ at room temperature. Finally, the CsPbI₃ grown inside nanoporous AAO templates exhibits exceptional phase stability over three months under ambient conditions, in which the resulting light‐emitting diode reveals a natural red color emission with very narrow bandwidth (full width at half maximum of 33 nm) at 702 nm. The universally applicable template‐based stabilization strategy can give in‐depth insights on the strain‐mediated phase transition mechanism in all‐inorganic perovskites.

High‐throughput density functional theory (DFT) methods are used to screen 1845 halide perovskite materials in search of nontoxic, stable, optimal bandgap materials with high photovoltaic efficiencies for use in single junction, quantum dot, and tandem Si‐perovskite solar cells. A total of 15 promising halide perovskite materials, including (CH₃NH₃)_0.75Cs_0.25SnI₃, ((NH₂)₂CH)Ag_0.5Sb_0.5Br₃, CsMn_0.875Fe_0.125I₃, ((CH₃)₂NH₂)Ag_0.5Bi_0.5I₃, and ((NH₂)₂CH)_0.5Rb_0.5SnI₃, are found.

Abstract

Two critical limitations of organic–inorganic lead halide perovskite materials for solar cells are their poor stability in humid environments and inclusion of toxic lead. In this study, high‐throughput density functional theory (DFT) methods are used to computationally model and screen 1845 halide perovskites in search of new materials without these limitations that are promising for solar cell applications. This study focuses on finding materials that are comprised of nontoxic elements, stable in a humid operating environment, and have an optimal bandgap for one of single junction, tandem Si‐perovskite, or quantum dot–based solar cells. Single junction materials are also screened on predicted single junction photovoltaic (PV) efficiencies exceeding 22.7%, which is the current highest reported PV efficiency for halide perovskites. Generally, these methods qualitatively reproduce the properties of known promising nontoxic halide perovskites that are either experimentally evaluated or predicted from theory. From a set of 1845 materials, 15 materials pass all screening criteria for single junction cell applications, 13 of which are not previously investigated, such as (CH₃NH₃)_0.75Cs_0.25SnI₃, ((NH₂)₂CH)Ag_0.5Sb_0.5Br₃, CsMn_0.875Fe_0.125I₃, ((CH₃)₂NH₂)Ag_0.5Bi_0.5I₃, and ((NH₂)₂CH)_0.5Rb_0.5SnI₃. These materials, together with others predicted in this study, may be promising candidate materials for stable, highly efficient, and nontoxic perovskite‐based solar cells.

A 1D ultrabroadband (>450 nm) optical cavity is designed following an inverse electromagnetic computational approach to optimally trap light in a thin film absorber layer. When this novel cavity concept is applied to a low bandgap organic solar cell, a broadband absorption enhancement is demonstrated beyond the conventional limit resulting from light trapping in an ergodic optical geometry.

Abstract

In the subwavelength regime, several nanophotonic configurations have been proposed to overcome the conventional light trapping or light absorption enhancement limit in solar cells also known as the Yablonovitch limit. It has been recently suggested that establishing such limit should rely on computational inverse electromagnetic design instead of the traditional approach combining intuition and a priori known physical effect. In the present work, by applying an inverse full wave vector electromagnetic computational approach, a 1D nanostructured optical cavity with a new resonance configuration is designed that provides an ultrabroadband (≈450 nm) light absorption enhancement when applied to a 107 nm thick active layer organic solar cell based on a low‐bandgap (1.32 eV) nonfullerene acceptor. It is demonstrated computationally and experimentally that the absorption enhancement provided by such a cavity surpasses the conventional limit resulting from an ergodic optical geometry by a 7% average over a 450 nm band and by more than 20% in the NIR. In such a cavity configuration the solar cells exhibit a maximum power conversion efficiency above 14%, corresponding to the highest ever measured for devices based on the specific nonfullerene acceptor used.