杂化太阳电池中异质结界面的修饰及其对电池光电性能的影响

有机-无机杂化太阳电池综合了有机、无机材料的优点,成本低、理论效率高,受到人们的广泛关注.杂化太阳电池的光活性层由无机半导体和有机共轭聚合物复合而成.当光照射到活性层上时,共轭聚合物吸收光子产生激子(电子-空穴对);激子迁移到有机给体-无机受体的异质结界面处发生解离而产生自由电子和空穴;自由电子和空穴分别向无机半导体和有机聚合物传输,从而实现电荷的分离和传导.激子在有机-无机异质结界面处的分离效率是影响电池性能的一个重要因素.有机、无机两相材料往往因为接触面积小以及相容性差使此两相材料接触不佳,激子迁移到此界面不能有效分离,从而严重影响了杂化太阳电池的效率.这个问题可以通过此界面的修饰加以改善.本文即综述了有机-无机异质结界面修饰的方法、作用和意义,并展望了杂化太阳电池未来的发展趋势和应用前景.

Heterojunction Interface Modification and Its Effect on the Photovoltaic Performance of Hybrid Solar Cells

Much attention has been focused on hybrid solar cells because of their low cost and high theoretical efficiencies. The photoactive layer of hybrid solar cells is composed of inorganic semiconductor and organic conjugated polymer. Excitons (electron-hole pairs) are formed upon the absorption of photons by the polymer. The excitons diffuse to the heterojunction interface between the organic donor and inorganic acceptor, and then dissociate to free electrons and holes. These electrons and holes then transfer to the inorganic and organic materials to realize charge separation and transportation. The exciton dissociation efficiency at the organic-inorganic heterojunction interface influences the photovoltaic performance of the cell. A small contact area and poor chemical compatibility between the organic and inorganic materials decrease the exciton dissociation efficiency, and thus the overall cell efficiency. This can be overcome by modifying the heterojunction interface. This paper reviews available interfacial modification methods, their function and significance, and explores prospects for the future development and application of hybrid solar cells.