Improvement of power conversion efficiency in photovoltaic-assisted UHF rectifiers by non-silicide technique applied to photovoltaic cells

Non-silicide PV cell structures were successfully applied to the photovoltaic (PV)-assisted UHF rectifier, which is one example realization of the "synergistic ambient energy harvesting" concept. Silicide blocking of PV cell area was experimentally verified to be effective for increasing photo-generated bias voltage, which resulted in the improved power conversion efficiency (PCE) of the rectifier by enhanced V-TH compensation effect. Increase in both transparency of light and quantum efficiency of PV cells obtained by eliminating silicide layer affects the PCE improvement almost equally. 25.8% of PCE was achieved under the conditions of an RF input power of -20 dBm, a frequency of 920 MHz, an output load of 47 k Omega O, and a typical indoor light irradiance level of 1W/m(2). In addition, when the non-silicide PV cell technique was applied to the voltage-boosted PV-cell structures, 32.1% peak PCE was achieved at 10W/m(2). (C) 2015 The Japan Society of Applied Physics