Open AccessReduced energy offset via substitutional doping for efficient organic/inorganic hybrid solar cells
Author(s) -
Xiao Jin,
Weifu Sun,
Qin Zhang,
Kelian Ruan,
Yuanyuan Cheng,
Haijiao Xu,
Zhongyuan Xu,
Qinghua Li
Publication year - 2015
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.00a444
Subject(s) - materials science , organic solar cell , acceptor , optoelectronics , photoluminescence , energy conversion efficiency , hybrid solar cell , solar cell , ion , doping , electron transfer , ultrafast laser spectroscopy , electron acceptor , photochemistry , polymer solar cell , optics , chemistry , physics , laser , organic chemistry , composite material , condensed matter physics , polymer
Charge carrier transport in bulk heterojunction that is central to the device performance of solar cells is sensitively dependent on the energy level alignment of acceptor and donor. However, the effect of energy level regulation induced by nickel ions on the primary photoexcited electron transfer and the performance of P3HT/TiO 2 hybrid solar cells remains being poorly understood and rarely studied. Here we demonstrate that the introduction of the versatile nickel ions into TiO 2 nanocrystals can significantly elevate the conduction and valence band energy levels of the acceptor, thus resulting in a remarkable reduction of energy level offset between the conduction band of acceptor and lowest unoccupied molecular orbital of donor. By applying transient photoluminescence and femtosecond transient absorption spectroscopies, we demonstrate that the electron transfer becomes more competitive after incorporating nickel ions. In particular, the electron transfer life time is shortened from 30.2 to 16.7 ps, i.e., more than 44% faster than pure TiO 2 acceptor, thus leading to a notable increase of power conversion efficiency in organic/inorganic hybrid solar cells. This work underscores the promising virtue of engineering the reduction of 'excess' energy offset to accelerate electron transport and demonstrates the potential of nickel ions in applications of solar energy conversion and photon detectors.