Electrical Engineering
      and Computer Sciences

Electrical Engineering and Computer Sciences

COLLEGE OF ENGINEERING

UC Berkeley

   

2010 Research Summary

Three dimensional nanopillar array photovoltaics on low cost and flexible substrates

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Zhiyong Fan, Haleh Razavi, Jae-won Do, Aimee Moriwaki, Onur Ergen, Yu-lun Chueh, Paul Leu, Johnny Ho1, Toshitake Takahashi, Lothar Reichertz2, Steven Neale, Kyoungsik Yu, Ming C. Wu, Joel Ager and Ali Javey

Berkeley Sensor and Actuator Center 00000000000 and Helios Solar Energy Research Center DE-AC02-05CH11231

In recent years, tremendous progress has been made in developing photovoltaics (PVs) that can be potentially mass employed. Of particular interest to cost-effective solar cells is to utilize novel device structures and materials processing for enabling acceptable efficiencies. Here, we report the direct growth of highly regular, single-crystalline nanopillar (NPL) arrays of optically active semiconductors in anodic alumina membrane (AAM) on aluminum substrates which are then configured as solar cell modules. The AAMs are fabricated with low cost and scalable anodization process for NPL array growth. To fabricate PV structure on such membranes, we have grown high density 3D single crystalline n-CdS NPLs with chemical vapor deposition method in AAMs, then embedded the 3D NPL structure in poly-crystalline thin films of p-CdTe, to enable high absorption of light and efficient collection of the carriers. Meanwhile, we have successfully embedded the PV structure in highly flexible PDMS substrates to enable bendable PV devices and the electrical measurements have demonstrated robustness of such devices. Through experiments and modeling, we demonstrate the potency of this approach for enabling highly versatile solar modules on both rigid and flexible substrates with enhanced carrier collection efficiency arising from the geometric configuration of the NPLs.

Figure 1
Figure 1: Nanopillar solar cells on glass and in PDMS with performance characterizations.

1Dept. of Materials Science and Engineering
2Materials Science Division, Lawrence Berkeley National Laboratory