Organic Solar Cells with Over 19% Efficiency Enabled by a 2D‐Conjugated Non‐Fullerene Acceptor Featuring Favorable Electronic and Aggregation Structures

Abstract

The π‐expansion of non‐fullerene acceptors is a promising method for boosting the organic photovoltaic performance by allowing the fine‐tuning of electronic structures and molecular packing. In this work, highly efficient organic solar cells (OSCs) are fabricated using a 2D π‐expansion strategy to design new non‐fullerene acceptors. Compared with the quinoxaline‐fused cores of AQx‐16, the π‐expanded phenazine‐fused cores of AQx‐18 induce more ordered and compact packing between adjacent molecules, affording an optimized morphology with rational phase separation in the blend film. This facilitates efficient exciton dissociation and inhibited charge recombination. Consequently, a power conversion efficiency (PCE) of 18.2% with simultaneously increasing Voc, Jsc, and fill factor is achieved in the AQx‐18‐based binary OSCs. Significantly, AQx‐18‐based ternary devices fabricated via a two‐in‐one alloy acceptor strategy exhibit a superior PCE of 19.1%, one of the highest values ever reported for OSCs, along with a high Voc of 0.928 V. These results indicate the importance of the 2D π‐expansion strategy for the delicate regulation of the electronic structures and crystalline behaviors of the non‐fullerene acceptors to achieve superior photovoltaic performance, aimed at significantly promoting further development of OSCs.

Unraveling the Structure–Property–Performance Relationships of Fused-Ring Nonfullerene Acceptors: Toward a C-Shaped ortho-Benzodipyrrole-Based Acceptor for Highly Efficient Organic Photovoltaics

“…One of the strategies employed is the substitution of Tz in the A’ unit with other heterocycles such as triazole, − selenadiazole, , and pyrazine moieties. − By implementing this modification, the resulting A-D N A’ N D-A NFAs can achieve PCEs comparable to that of Y6. Consequently, the inclusion of the A’ moiety in the Y6-series materials is widely recognized as a crucial design element.…”

Machine-learning-guided prediction of photovoltaic performance of non-fullerene organic solar cells using novel molecular and structural descriptors

“…1–19 Several research groups have reported PCEs of more than 19% in single bulk OSCs. 20–26 Although high-performance devices have been frequently demonstrated, their PCE and open-circuit voltage ( V OC ) still lag behind those of other competing technologies such as Si, GaAs, and perovskite solar cells. Also, these parameters are much lower than the attainable Shockley Queisser (SQ) limit, which indicates the scope for further improvement in their performance.…”

Ternary organic solar cells with a selenophene-containing donor guest achieve a high efficiency of 18.41%

“…[1][2][3][4][5][6][7][8][9][10][11][12] Power conversion efficiencies (PCEs) of over 19% have been achieved for both single junction and tandem OSCs. [13][14][15][16][17][18][19][20][21][22] Combining the unique advantages of light weight, large-area fabrication, and flexibility, BHJ-OSCs show great commercialization prospects. [23][24][25][26][27][28][29] To date, the traditional binary BHJ-OSCs consisting of a polymer donor and a nonfullerene acceptor (NFA) in the active layer have demonstrated great success; however, the shortcomings, such as inferior light capturing, higher energy loss (E loss ), lower open-circuit voltage (V oc ), and fill factor (FF), should not be neglected.…”

“…1–12 Power conversion efficiencies (PCEs) of over 19% have been achieved for both single junction and tandem OSCs. 13–22 Combining the unique advantages of light weight, large-area fabrication, and flexibility, BHJ-OSCs show great commercialization prospects. 23–29…”