The origin of voltage deficits in polycrystalline cadmium selenide telluride (CdSeTe) solar cells is unclear. Here, we present a comprehensive voltage loss analysis performed on state-of-the-art CdSeTe devices—fabricated at Colorado State University and First Solar—using photoluminescence techniques, including external radiative efficiency (ERE) measurements. More specifically, we report the thermodynamic voltage limit V_oc,ideal, internal voltage iV_oc and external voltage V_oc of partially and fully finished cells fabricated with different dopant species, dopant concentrations and back contacts. Arsenic-doped aluminium-oxide-passivated cells made at Colorado State University present remarkably high ERE (>1%)—translating into iV_oc above 970 mV—but suffer from poor back-contact selectivity. On the other hand, arsenic-doped devices from First Solar present almost perfect carrier selectivity (V_oc = iV_oc), leading to V_oc above 840 mV, and are limited by recombination in various parts of the device. Thus, development of contact structures that are both passivating and selective in combination with highly luminescent absorbers is key to reducing voltage losses.

多晶碲化硒化镉 (CdSeTe) 太阳能电池中电压不足的原因尚不清楚。在这里，我们使用光致发光技术（包括外部辐射效率 (ERE) 测量）对最先进的 CdSeTe 器件（由科罗拉多州立大学和 First Solar 制造）进行了全面的电压损耗分析。更具体地说，我们报告了热力学电压极限V _oc,ideal、内部电压 i V _oc和外部电压V _oc用不同的掺杂剂种类、掺杂剂浓度和背接触制造的部分和完全完成的电池。科罗拉多州立大学制造的掺砷氧化铝钝化电池具有非常高的 ERE（>1%）——转化为高于 970 mV 的 i V _oc ——但背接触选择性较差。另一方面，First Solar 的砷掺杂器件呈现出几乎完美的载流子选择性 ( V _oc  = i V _oc )，导致V _oc高于 840 mV，并且受到器件各个部分的复合限制。因此，开发既具有钝化又具有选择性的接触结构与高发光吸收体相结合是降低电压损耗的关键。