探索提高光电极太阳能转换效率的新方法  

New Methods to Improve Solar Energy Conversion Efficiency of Photoelectrodes

作　　者：罗文俊[1] 李朝升[1] 邹志刚[1] 

机构地区：[1]南京大学环境材料与再生能源研究中心,江苏南京210093

出　　处：《中国材料进展》2009年第1期54-59,共6页Materials China

基　　金：国家973项目经费资助(2007CB613305)

摘　　要：光电化学电池制氢是解决能源短缺的可能途径之一,然而太阳能转换效率低限制了其大规模实用化。提出了通过提高量子转换效率(IPCE)和减小带隙等手段来提高太阳能转换效率。利用异质结中的内建电场,有利于电子空穴分离,从而提高量子转换效率。以WO3/Fe2O3异质结光电极为例,在400～530nm波长范围内,其量子转换效率高于单一的WO3和Fe2O3电极的总和。窄带隙半导体材料能够吸收更多的可见光,从而提高太阳能转换效率。窄带隙材料可以通过固溶体方法对宽带隙半导体的价带进行调控来获得。以(SrTiO3)1-x·(LaTiO2N)x(0≤x≤0.40)为例,随着x的增加,价带提高而带隙逐渐减小。当x=0.4时可见光响应超过600nm,IPCE的最大值4.6%出现在410nm左右。窄带隙材料也可以通过固溶体方法对宽带隙半导体的导带进行调控来获得。以InxGa1-xN(0≤x≤0.20)为例,固溶体的带隙随着x的增加而逐渐减小,固溶体带隙减小主要是由于导带降低引起的;当x=0.2时可见光响应超过480nm,在400～430nm波长范围内最高IPCE达到9%。A photoelectrochemical cell is one of the methods to resolve the energy shortage problem. However, low solar energy conversion efficiency limits its applications on a large scale. In this paper, it was proposed that enhancing incident photon conversion efficiency （IPCE） or making wide band gap semiconductors narrow improve the solar energy conversion efficiency. Heterojunction photoelectrodes can improve IPCE by separating photo - generated electron - hole pairs at built - in electric field. For example, the IPCE of WO3/Fe2O3 heterojunction with the wavelength in the range of 400 ～ 530 nm is higher than the addition of WO3 and Fe2 O3 electrode. On the other side, narrow band gap semiconductor can absorb more visible light and make the conversion efficiency of a photoelectrode higher. Narrow band gap semiconductors can be obtained by adjusting the valence bands of wide band gap semiconductors by solid solution method. For example, the band gaps of the （ SrTiO3 ） 1 - x （ LaTiO2 N） x （ 0≤ x ≤ 0. 40 ） solid solution decrease with increasing x because the valence bands are raised. The visible - light response wavelength of x = 0. 4 is longer than 600nm and the maximum IPCE at 410 nm is about 4. 6%. Narrow band gap semiconductors can be obtained by adjusting the conduction band of wide band gap semiconductors. For example, the band gaps of the InxGa1-xN （0 ≤ x≤ 0. 20 ） solid solution decrease with increasing x because the conduction bands are lowered. The visible - light response wavelength of x = 0.2 is longer than 480nm and the maximum IPCE at 400 -430 nm is about 9%.

关 键 词：光电化学电池 WO3/Fe2O3异质结 (SrTiO3)1-x.(LaTiO2N)x InxGa1-xN 太阳能制氢 

分 类 号：TK511.4[动力工程及工程热物理—热能工程]