Data for: Highly efficient ternary polymer solar cells based on a novel double-cabled third component with the same molecular fragments of donor and acceptor moieties

Organic thin film solar cells have attracted wide attention because of their low-cost, flexibility, light-weight and solution-processiblity. With continuous efforts in material designing and device engineering, the power conversion efficiency (PCE) of the polymer solar cells (PSCs) has beyond 15%. The novel non-fullerene acceptors with broad absorption spectra and high electron mobility play a key role for PCE enhancement. However, the low absorption of non-fullerene materials in the short-wave direction and the full width at half maximum (FWHM) of the absorption spectra for active layer materials are only around 100 nm, which limits the further improvement of PCE. Obviously, ternary PSCs can easily enhance the light-harvesting of the sunlight to promote the charge-generation. Furthermore, the ternary structure can optimize the phase separation of the donor and acceptor materials, and can also improve the driving force for charge transfer and facilitate electron transport in PSCs. Therefore, rational selection of the third component is crucial for the performance of the ternary PSCs. The method of trial and error is still the main approach to find the third component in ternary PSCs, and there is no universal principle guiding for the molecular design of the third component. Actually, the absorption spectra of the double-cabled molecules are the superimposed absorption of the donor backbones and the acceptor pendants with certain blue-shift caused by the enhanced steric hindrance. Benefit from this blue-shift, the double-cable molecule should be the idea third component to construct ternary solar cells with backbone donor and pendant acceptor, and this finding should be the universal design principle for the synthesis of the third component, providing a good idea to further improve the PCE of the PSCs. Herein, we report a novel double-cabled material ITLYBT with the same molecular fragments of donor and acceptor moieties. The absorption spectra of ITLYBT are the superimpose of the donor backbones and the acceptor pendants with nearly 200 nm blue-shift caused by the enhanced steric hindrance, which works as an ideal third component for highly efficient ternary PSCs to broaden and complement the absorption spectra of the photoactive layer. By introducing ITLYBT into PBDB-T-2F:ITIC-4F blend, the ternary device shows enhanced Jsc and Voc, and the over PCE increases from 12.50% to 13.14% due to the optimized phased separation and reduced charge recombination. These results indicate that double-cabled molecule is an ideal third component for construction high performance ternary PSCs.

有机薄膜太阳能电池凭借低成本、柔性、轻质以及可溶液加工的特性，受到了广泛关注。经过材料设计与器件工程领域的持续深耕，聚合物太阳能电池（polymer solar cells, PSCs）的功率转换效率（power conversion efficiency, PCE）已突破15%。具备宽吸收光谱与高电子迁移率的新型非富勒烯受体，是提升PCE的核心因素。然而，非富勒烯材料在短波方向的吸收不足，且活性层材料吸收光谱的半高宽（full width at half maximum, FWHM）仅约100 nm，这一缺陷限制了PCE的进一步提升。
显然，三元聚合物太阳能电池可有效增强对太阳光的光捕获能力，进而促进电荷生成过程。此外，三元结构能够优化给体与受体材料的相分离，同时提升电荷转移驱动力，助力聚合物太阳能电池中的电子传输。因此，合理遴选第三组分对三元PSCs的性能至关重要。当前，试错法仍是寻找三元PSCs第三组分的主流途径，尚未有通用原则可指导第三组分的分子设计。
实际上，双缆型分子的吸收光谱是给体主链与受体侧链吸收的叠加，且由于空间位阻增强会产生一定的蓝移。得益于这一蓝移效应，双缆型分子应当是构建以给体主链-受体侧链为基础的三元太阳能电池的理想第三组分，这一发现也应成为合成第三组分的通用设计原则，为进一步提升PSCs的PCE提供了全新思路。
本文报道了一种新型双缆型材料ITLYBT，其分子片段与给体、受体单元完全一致。ITLYBT的吸收光谱为给体主链与受体侧链的叠加吸收，且因空间位阻增强产生了近200 nm的蓝移，可作为理想的第三组分，用于高效三元PSCs以拓宽并补充光活性层的吸收光谱。
将ITLYBT引入PBDB-T-2F:ITIC-4F共混体系后，三元器件的短路电流密度（Jsc）与开路电压（Voc）均得到提升，得益于优化的相分离与抑制的电荷复合，整体PCE从12.50%提升至13.14%。上述结果表明，双缆型分子是构建高性能三元PSCs的理想第三组分。