研究目的
Investigating the switchable photocurrent generation in an ultra-thin resonant cavity solar cell by changing the refractive index of Mg due to hydrogen absorption.
研究成果
The combination of an ultra-thin a-Ge:H absorber layer and a switchable rear contact is able to reach switchable photocurrent generation, based on switchable absorption enhancement. This new approach decouples the development of the absorber layer from the optical switching. Despite using a non-optimized device, an overall cell efficiency of 1.78% was reached.
研究不足
The efficiency of the solar cell must be improved. The switching process must be adapted for larger scale applications. The energy cost to use a switchable solar window must not exceed its gain in electric power.
1：Experimental Design and Method Selection
The study employs a thin film photovoltaic layer stack based on an amorphous germanium absorber layer combined with a thin Mg/Pd mirror to create a switchable solar cell. The optical and electrical properties of the switchable device are modeled and experimentally proven.
2：Sample Selection and Data Sources
The device layer stack consists of an electrical front contact, a p-i-n structure for charge carrier separation, and the switchable rear contact. The device is illuminated from the glass side, meaning the cell is in superstrate configuration.
3：List of Experimental Equipment and Materials
Silicon and germanium layers were deposited using plasma enhanced chemical vapor deposition (PECVD). MoOx, Ti, Mg, and Pd layers were deposited by electron beam evaporation. Optical measurements were performed with a Cary UV-Vis 5000 with an integrating sphere. Scanning electron microscopy imaging and focused ion beam milling was done using a Zeiss Neon Crossbeam.
4：Experimental Procedures and Operational Workflow
The device is exposed to hydrogen atmosphere for 20 minutes at room temperature to reach the transparent state and tempered at 50 °C in ambient air for 20 minutes to return to the absorbing state.
5：Data Analysis Methods
The software package Scout/CODE by W. Theiss was used to create models for the transmission, the reflection, and the absorption of the complete device by 1D transfer matrix method. Dielectric functions of the respective layers were created by fitting optical model functions to measured transmission and reflection data of single layers for near normal incidence.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
