Controllable Preparation, Photoelectric Properties Of P3HT/CdSe And P3HT/CuInSe₂Hybrid Nanocrystals

The energy crisis and enviroment pollution have promote the development of all kinds of solar cells. In particular, Organic/inorganic hybrid solar cells have caught people’s intentions because of low cost、simple to assemble and easy commercialization. But by now the efficiency of the solar cells is low, and one of the primary causes is that inorganic nanocrystals used as the acceptor are usually capped with organic aliphatic ligands, such as trioctylphosphine oxide (TOPO) and oleic acid (OA). The presence of organic aliphatic ligands prevents electrons transferring from the photoexcited polymer to the nanoparticles. This negative effects of the capping organic aliphatic ligands on charge exchange are eliminated and the step of transferring inorganic nanocrystals into the polymer solution for exchange can be bypassed, achieving direct synthesis of nanoparticles with photoelectronic polymer as ligands. Because CdSe and CuInSe2with direct bandgaps semiconductors are the common inorganic components in organic-inorganic solar cells, We employ organic semiconductor P3HT as ligands to synthesize P3HT-CdSe and P3HT-CuInSe2organic-inorganic hybrid nanocrystals. The main work is as follow:1. Firstly, we synthesized uniform sized CdSe superstructures nanocrystals using pyrolysis method and we studied the effects of reaction time and concentration of reactants and reaction temperature on the morphology of CdSe superstructures. Then we employed P3HT as the ligands to synthesize P3HT capped CdSe superstructures and realize in-situ hybrid. Also, we studied the effects of the P3HT amount on the morphology and photoelectric property of P3HT-CdSe superstructures.2. P3HT capped CdSe superstructures were used as a model material to fabricate the hybrid solar cells with structures of FTO/density Ti02/porous TiO2/P3HT-CdSe/P3HT/Au and PEDOT:PSS/P3HT-CdSe/P3HT/Al. The solar cell with the fommer structure did’t show an effective solar cell efficiency, but had a0.15mA forward current and a0.05mA reverse leakage current. Then we adjusted the structure of the solar cell. The hybrid solar cell with the latter structure exhibited the p-n property of a0.45mA forward current and a0.01mA reverse leakage current and had an open circuit voltage (Voc) of540mV, a short-circuit current density (Jsc) of4.25mA/cm2and a fill factor FF of0.575, yielding an overall solar-to-electric energy conversion efficiency (η) of1.32%.3. CuInSe2and P3HT-CuInSe2superstructures were synthesized using pyrolysis method. The effect of kind of reactants and concentration of reactants on the morphology of CdSe superstructures were studied. P3HT-CuInSe2was employed as absorption materials to assemble solar cells with a structure of FTO/PEDOT:PSS/P3HT-CuInSe2/P3HT/Al. The solar cell exbited a good p-n characteristic of0.6mA forward current and a0.07mA reverse leakage current, Voc of270mV, Jsc of0.04mA/cm2, and FF of0.235, yielding η of0.0025%.