CuS纳米掺杂聚合物光伏器件中的电荷传输

Carrier Transport in Photovoltaic Devices Based on Polymer/CuS Nanoparticles Composites

制备了CuS纳米颗粒掺杂聚合物MEH-PPV的光伏器件。研究了3种MEH-PPV/CuS掺杂比例(1∶1.00、1∶1.25、1∶2.50)光伏器件的光电流响应谱与动态双脉冲光电流响应,结果表明:CuS良好的导电性可以改善器件中的载流子传输,从而提高光电流响应值;在较低的CuS纳米颗粒掺杂浓度下,MEH-PPV与CuS纳米颗粒间形成的界面有可能造成电荷积累,会直接影响到光电流响应值;在CuS纳米颗粒掺杂浓度较高时,电荷积累现象基本消失,这是因为高浓度时形成的聚集相改善了两种载流子的传输,抑制了MEH-PPV/CuS界面的电荷积累。

The transport mechanism of photogenerated carriers in the composite films based on poly[2-methoxy,5-（2＇-ethyl- hexyloxy）-l,4,-phenylene-vinylene]（MEH-PPV） doped with CuS nanoparticles is investigated by the steady-state photocurrent spectra and dynamic double-pulse photocurrent response. An obvious charging effect is found at lower concentration of CuS nanoparticles, while at high concentration, the same feature is absent. The charging effect is attributed to charge ac cumulation at the interface between MEH-PPV and CuS nanoparticles, which directly destroys the photocurrent responses of composite devices. It is concluded that doping CuS into MEH-PPV at low concentration causes trap states, and filling and emptying traps leads to charging and discharging effect respectively. At high concentration of CuS nanoparticles,the aggregation scale becomes larger and the double polar transport of charge carriers is improved,which inhibits the charge accumulation at the interface of MEH-PPV/CuS.