Hybrid Inorganic-Organic Perovskite Halide Photovoltaics

The fundamental scientific and engineering research in the design and realization of new electronic materials for thin film photovoltaics (PV) for flexible electronics is being investigated. A significant portion of this research effort is devoted to investigating, researching and developing special optical materials for thin film PV. Thin film polycrystalline low cost alternatives to silicon have emerged. Recently, the methylammonium lead tri-iodide CH3NH3PbI3 perovskites have attracted a lot of attention as a possible absorber material for thin film solar cells due to their bandgap energy, high optical absorption coefficients and low-cost solution-processing deposition approaches. Perovskite absorber materials are very inexpensive to synthesize and simple to manufacture, making them an extremely commercially viable option. Our research focuses on the investigation, study and development of efficient and cost effective perovskite thin films and solar cells. Our group is also investigating tandem solar cells with perovskite and silicon solar cells; lead-free perovskites with lead replaced by tin; and other novel approaches.

Gamma and X-ray CZT Room Temperature Radiation Detectors

Cadmium Zinc Telluride (CZT), a semiconductor material is well suited for good charge collection efficiency and high energy resolution room temperature gamma-ray radiation detection. Room temperature CZT detectors are being investigated in collaboration with BNL's Nonproliferation and National Security group. Research is required to improve quality, compositional homogeneity, and the charge-transport characteristics of CZT crystals, to increase the yield and lower the cost. In support, our group fabricate and characterize CZT detectors, prepare and polish CZT crystals. Spectrums are collected and analyzed. Current-voltage (I-V) measurements are performed. Resistivities, leakage current, drift time, amplitute and mobility-lifetime (mt) product is analyzed.

Solar-blind Ultraviolet (UV) Photodetectors

UV detectors that have a high sensitivity to radiation with wavelengths lower than 280 nm are called solar-blind UV photodetectors. The beta gallium oxide (b-Ga2O3) semiconductor, with its direct and wide bandgap of ~4.9 eV in the deep UV region, is one of the most promising candidates for high-performance solar-blind UV photodetectors. Our group is investigating the use b-Ga2O3 as the semiconductor material to create a low-energy consumption, more effective and lower cost solar-blind UV photodetector. Beyond its wide bandgap, major advantages of the b-Ga2O3 semiconductor include its ability to reduce dark current, permitting operations of the detector at room temperatures, and the high mobility of charge carriers in b-Ga2O3 enables faster response times from detectors.

  SEM/FIB cross-section image of perovskite thin-film solar cell.

NSF LSAMP and Summer Research at BNL

BNL Summer Research Video