光(guang)(guang)伏發(fa)電(dian)(dian)的(de)主要原(yuan)(yuan)理(li)是(shi)半(ban)導(dao)體(ti)的(de)光(guang)(guang)電(dian)(dian)效應(ying)。當光(guang)(guang)子(zi)(zi)(zi)(zi)撞(zhuang)擊金(jin)屬(shu)時(shi),其能量(liang)可以(yi)被金(jin)屬(shu)中的(de)一個(ge)(ge)電(dian)(dian)子(zi)(zi)(zi)(zi)完全吸(xi)收。電(dian)(dian)子(zi)(zi)(zi)(zi)吸(xi)收的(de)能量(liang)大到足以(yi)克服(fu)金(jin)屬(shu)原(yuan)(yuan)子(zi)(zi)(zi)(zi)內部(bu)的(de)庫侖(lun)力做功并從金(jin)屬(shu)表面逃逸(yi),成(cheng)為(wei)光(guang)(guang)電(dian)(dian)子(zi)(zi)(zi)(zi)。硅有四(si)個(ge)(ge)外(wai)層電(dian)(dian)子(zi)(zi)(zi)(zi)。如果純(chun)硅摻雜有五個(ge)(ge)外(wai)層電(dian)(dian)子(zi)(zi)(zi)(zi)的(de)原(yuan)(yuan)子(zi)(zi)(zi)(zi),比如磷原(yuan)(yuan)子(zi)(zi)(zi)(zi),就會變(bian)成(cheng)N型(xing)半(ban)導(dao)體(ti)。如果純(chun)硅摻雜有三個(ge)(ge)外(wai)層電(dian)(dian)子(zi)(zi)(zi)(zi)的(de)原(yuan)(yuan)子(zi)(zi)(zi)(zi),例如硼原(yuan)(yuan)子(zi)(zi)(zi)(zi),就形成(cheng)了P型(xing)半(ban)導(dao)體(ti)。P型(xing)和N型(xing)結(jie)合在一起,接觸(chu)面就會形成(cheng)電(dian)(dian)位差,成(cheng)為(wei)太陽(yang)能電(dian)(dian)池。當太陽(yang)光(guang)(guang)照(zhao)射到pn結(jie)上時(shi),電(dian)(dian)流(liu)從P型(xing)側流(liu)向(xiang)N型(xing)側,形成(cheng)電(dian)(dian)流(liu)。