Theoretical investigation on exciton-dissociation and charge-recombination processes of PC61BM-PTDPPSe interface

Designing and synthesizing novel electron-donor polymers with the high photovoltaic performances has remained a major challenge and hot issue in organic electronics. In this work, the exciton-dissociation (k dis ) and charge-recombination (k rec ) rates for the PC61BM-PTDPPSe system as a promising polymer-based solar cell candidate have been theoretically investigated by means of density functional theory (DFT) calculations coupled with the non-adiabatic Marcus charge transfer model. Moreover, a series of regression analysis has been carried out to explore the rational structure-property relationship. Results reveal that the PC61BM-PTDPPSe system possesses the large open-circuit voltage (0.77 V), middle-sized exiton binding energy (0.457 eV), and relatively small reorganization energies in exciton-dissociation (0.273 eV) and charge-recombination (0.530 eV) processes. With the Marcus model, the k dis , k rec , and the radiative decay rate (k s ), are estimated to be 3.167×10(11) s(-1), 3.767×10(10) s(-1), and 7.930×10(8) s(-1) respectively in the PC61BM-PTDPPSe interface. Comparably, the k dis is as 1∼3 orders of magnitude larger than the k rec and the k s , which indicates a fast and efficient photoinduced exciton-dissociation process in the PC61BM-PTDPPSe interface. Graphical Abstract PTDPPSe is predicted to be a promising electron donor polymer, and the PC61BM-PTDPPSe system is worthy of further device research by experiments.

n-Type organic semiconductors in organic electronics

Organic semiconductors have been the subject of intensive academic and commercial interest over the past two decades, and successful commercial devices incorporating them are slowly beginning to enter the market. Much of the focus has been on the development of hole transporting, or p-type, semiconductors that have seen a dramatic rise in performance over the last decade. Much less attention has been devoted to electron transporting, or so called n-type, materials, and in this paper we focus upon recent developments in several classes of n-type materials and the design guidelines used to develop them.