Toward High Efficiency Polymer-Nanoparticle Hybrid Solar Cell
Hybrid materials made from conducting polymer-nanoparticle are attractive for solar cell because of the prospect of light weight, low cost, high throughput, high energy density using reel-to-reel or spray deposition on flexible substrate. In this research, we are investigating thermal stable polymer-metal oxide hybrid material for solar cell. We are able to greatly improve the efficiency of the hybrid solar cell by fabricating highly ordered nano structure hybrids, studying the morphology and interlayer characteristics of hybrid, and modifying the surface of metal oxide.
The device can be either in forward structure or invert structure. The inclusion of TiO2 nanorods into conducting polymer increases the ordering of polymer and its absorption spectrum was red shifted; the exciton life has been decreased to less than half of the neat polymer. The efficiency of P3HT-TiO2 solar cell can be increased by 2.5 times by inserting a TiO2 nanorod layer between the hybrid active layer and Al electrode due to the enlargement of the interconnecting network between the hybrid and electrode. The effect of polymer molecular weight on the nanoscale morphology that related to the performance of P3HT-TiO2 hybrid solar cell was studied by scanning near field optical microscopy (SNOM), atomic force microscopy (AFM) and confocal Raman microscopy.
The results are correlated well with the carrier transport behavior of different molecular weight polymer investigated by the time-of-flight technique. The solar cell fabricated from surface modified TiO2 nanoparticles with bandgap tuned linker and P3HT hybrid can have an order increase in efficiency. The efficiency of the device is further improved by using newly developed self assembled highly ordered nano structure copolymers and low bandgap conducting copolymers to power conversion efficiency more than 7.3%.