Title :
Thick-emitter silicon solar cells
Author :
Cuevas, A. ; Balbuena, M.
Author_Institution :
Inst. de Energia Solar, Univ. Politecnica de Madrid, Spain
Abstract :
Some results of a theoretical optimization of the emitter region of a silicon solar cell are presented. The best compromise between recombination current, quantum collection efficiency, and sheet resistance is found for relatively thick, moderately doped, surface-passivated emitters. Experimental evidence is given to support the thick-emitter philosophy. Efficiencies up to 19.1% (global AM1.5) and open-circuit voltages up to 670 mV (25 degrees C) have been measured in 2*2 cm2 cells having a textured surface, a single-layer antireflection coating, and a 7% grid shadowing. Even though the junction depth is between 0.8 and 2.4 mu m, the internal quantum efficiency is still high, ranging from 91% to 75% for lambda =400 nm. The experiments include a determination of the influence of the metal grid coverage factor on open-circuit voltage, leading to the prediction of a high-voltage (660 mV) and high-efficiency (18.6%) capability for such an industrial metallization technology as screen printing.
Keywords :
antireflection coatings; electron-hole recombination; elemental semiconductors; passivation; silicon; solar cells; 15.1 percent; 18.6 percent; 2 cm; 25 degC; 660 mV; 670 mV; Si solar cells; grid shadowing; internal quantum efficiency; open-circuit voltages; quantum collection efficiency; recombination current; semiconductors; sheet resistance; single-layer antireflection coating; surface-passivated emitters; textured surface; Coatings; Electrical resistance measurement; Metals industry; Photovoltaic cells; Radiative recombination; Shadow mapping; Silicon; Surface resistance; Surface texture; Voltage;
Conference_Titel :
Photovoltaic Specialists Conference, 1988., Conference Record of the Twentieth IEEE
Conference_Location :
Las Vegas, NV, USA
DOI :
10.1109/PVSC.1988.105737