WANG Yao-ming, LUO Wen-jun, OUYANG Shu-xin, LI Zhao-sheng, YU Tao, ZOU Zhi-gang. Enhancement in Photoelectric Conversion Properties of SrTiO<sub>3</sub>/α-Fe<sub>2</sub>O<sub>3</sub> Heterojunction Photoanode[J]. Chinese Journal of Luminescence, 2007,28(2): 277-281
WANG Yao-ming, LUO Wen-jun, OUYANG Shu-xin, LI Zhao-sheng, YU Tao, ZOU Zhi-gang. Enhancement in Photoelectric Conversion Properties of SrTiO<sub>3</sub>/α-Fe<sub>2</sub>O<sub>3</sub> Heterojunction Photoanode[J]. Chinese Journal of Luminescence, 2007,28(2): 277-281DOI:
并对该光电极进行了XRD、SEM、紫外-可见透射光谱的表征。在三电极光电化学测试系统中对薄膜的光电流-电压特性、入射光子电流转化效率(Incident photon to current efficiency
IPCE)对波长的依赖性进行了表征。在相同的Xe灯照射条件下
SrTiO
3
/α-Fe
2
O
3
异质结光电极的光电流及IPCE值大于单一的SrTiO
3
、α-Fe
2
O
3
各自的光电流及IPCE值
这与理论预测的结论一致。
Abstract
The photoelectrochemical cells based on semiconductor-liquid junctions have attracted much attention because of their potential application
such as solar energy converters. In the cell system
it is important to produce the high efficiency photoelectrodes that are stable in aqueous solution and that absorb a significant portion of the solar spectrum effectively. Much effort has been done to find new materials and new electrode structures in order to produce efficient photoelectrodes. Along with its abundance and low cost
α-Fe
2
O
3
has narrow band gap
strong absorptivity in the visible range and good stability in aqueous solution. So it has been of considerable interest in its use as a photocatalyst and a photoelectode. However
the photocurrent quantum efficiency of α-Fe
2
O
3
is too low to limit its further application in converting solar energy. In general
recombination of electrons and holes cased by low mobilities of holes and trapping of electrons by oxygen-deficient iron sites are considered to be responsible for the low conductivities and poor photocurrent efficiencies of iron oxide photoelectrode.To suppress the recombination of electrons and holes thus to improve the photocurrent quantum efficiency
the semiconductor films of SrTiO
3
α-Fe
2
O
3
and their heterojunction SrTiO
3
/α-Fe
2
O
3
were prepared on FTO (SnO
2
:F on glass) substrates by the spin-coating method. The XRD pattern
SEM and transmission spectra of SrTiO
3
/α-Fe
2
O
3
film photoanode were characterized in our experiments. The anodic photocurrent-potential characteristics and the action spectra were studied in a three-electrode cell employing the film electrode as the working electrode with the electrolyte Na
2
SO4(0.2 mol/L
pH≈7.5). It was found that under 0.3 V bias voltage
the photocurrent and the incident photon to current conversion efficiency (IPCE) of the SrTiO
3
/α-Fe
2
O
3
film was higher than that of SrTiO
3
or α-Fe
2
O
3
films alone
which is consonant with our theoretical calculation conclusions by using the standard CASTEP package.