STUDY OF N-TYPE SEMICONDUCTING CADMIUM CHALCOGENIDE-BASED PHOTOELECTROCHEMICAL CELLS EMPLOYING POLYCHALCOGENIDE ELECTROLYTES
STUDY OF N-TYPE SEMICONDUCTING CADMIUM CHALCOGENIDE-BASED PHOTOELECTROCHEMICAL CELLS EMPLOYING POLYCHALCOGENIDE ELECTROLYTES
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DOI：
10.1021/ja00451a001
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发表时间：
1977-01-01
影响因子：
15
通讯作者：
WRIGHTON, MS
中科院分区：
文献类型：
--
作者：
ELLIS, AB;KAISER, SW;WRIGHTON, MS
本文报道了X=S、Se和Te的X_2/X“2_电解液中Cd_x基光电化学电池的研究。对于九种电极/电解液组合中的八种，我们证明了n型半导体单晶CDX光电极对阳极溶解是稳定的。仅对于CdTein S2_/S“2_，我们发现添加的硫化物的氧化不会抑制通常在水溶液中存在的CDX的分解。对于所有剩余的八种电解液/电极组合，添加的硫化物在光电极上被氧化，其速度排除了CDX的阳极溶解。对于稳定的组合，每个电解液都能够在光电极上被氧化，然后在暗对电极上被还原，以完成一个没有净化学变化的循环。对于所有九种电解液/电极组合和碱性水中的CDX，与X2-的氧化或与析氧有关的氧化还原水平位于半导体-电解液界面的价带和导带位置之间。因此，所有情况下都满足X2-氧化或H2O放出O2的能量要求，但显然动力学因素决定了X2-或H2O的氧化速度是否快于阳极溶解，这在能量上也是可行的。对于稳定的电极/电解液组合，可以实现光能到电能的转换，单色可见光的转换效率为>；10%。对于在TE2-/Te22-电解液中的CdTe或CdSe，输入功率密度为>；500 mW/cm2可以在不降低性能的情况下以几个百分点的效率转换。最大功率转换效率下的输出电压约为0.4V。
Studies of CdX-based photoelectrochemical cellsin X2_/X „2_ electrolytes are reported for X= S, Se, and Te. For eight of the nine electrode/electrolyte combinations we have demonstrated that the n-type semiconducting single-crystal CdX photoelectrodes are stable to anodic dissolution. Onlyfor CdTein S2_/S „2_ do we find that oxidation of the added chalcogenide does not quench the decomposition of CdX typically found in aqueous electrolytes. For all eight remaining electrolyte/elec-trode combinations the added chalcogenide is oxidized at thephotoelectrode at a rate which precludes anodic dissolution of the CdX. Forthe stable combinations each electrolyte is capable of being oxidized at the photoelectrode and subsequently re-duced at the dark counter electrode to complete a cycle where no net chemical change obtains. For all nine electrolyte/elec-trode combinations and for the CdX in alkaline H2O, the redox level associated with the oxidationof X2-or with O2 evolution is between the valence band and conduction band positions at the semiconductor-electrolyte interface. Thus, energetic require-ments for X2-oxidation or O2 evolution from H2O are met in all cases, but apparently kinetic factors control whether oxida-tion of X2-or of H2O will be fast compared to anodic dissolution, which is also energetically feasible. For the stable electrode/electrolyte combinations, conversion of optical to electrical energy can be accomplished with efficiencies of> 10% for mono-chromatic visible light. For CdTe or CdSe in the Te2-/Te22-electrolyte input power densities of> 500 mW/cm2 can be con-verted with a few percent efficiency with no deterioration of properties. Output voltages at maximum power conversion effi-ciency are of the order of 0.4 V.