Organic Solar Cells

Research progress on all-small-molecule organic solar cell

Organic solar cells have received widespread attention in recent years as a new generation of solar cell technology. Compared with traditional silicon-based solar cells, organic solar cells have the advantages of low cost, flexibility, and large-area printing preparation.

The current mainstream strategy for the preparation of high-efficiency organic solar cell is to use polymer donors and non-fullerene acceptor materials to construct active layers. However, polymer materials usually have problems such as difficulty in accurately controlling molecular weight and dispersion, difficulty in purification, and poor batch stability of the materials. The reproducibility of the efficiency of correspondingly prepared organic solar cell is reduced, which is not conducive to large-scale commercial applications.

The molecular weight of small organic molecules can be accurately synthesized, easy to purify, and has good batch stability, which is conducive to large-scale preparation. Therefore, all-small-molecule organic solar cells have high commercial application potential. However, because the donor and acceptor of all-small-molecule cells have small molecular structures, it is difficult to form the ideal bicontinuous interpenetrating network morphology like polymer films. Too strong donor crystals can cause serious donor and acceptor blending, while too weak donors are not conducive to tight π-π accumulation between donor molecules, which reduces charge transport. Therefore, the phase morphology of all-small-molecule cells is difficult to regulate, which makes its photoelectric conversion efficiency always at a low level.

Recently, Ge Ziyi’s team of Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences reported a non-fullerene all-small-molecule organic solar cell with 13.34% photoelectric conversion efficiency, which is the highest efficiency of all-small-molecule organic solar cell