Recent progress of colloidal quantum dot based solar cells
Wei Huiyun1, Li Dongmei2, 3, †, Zheng Xinhe1, ‡, Meng Qingbo2, 3
       

(color online) (a) Surface-bound molecules shift quantum dot energy levels (leading to p- or n-type behavior) by inducing variable surface dipoles. (b) At the interface between quantum dot layers with different surface binding groups, another dipolar shift modifies the energy-level alignment crucial to device performance.[130]