Effect of reduced selectivity of contacts on the current-potential characteristics and conversion performance of solar cells

Considering a simple configuration of a solar cell formed by a light-absorbing material sandwiched between two selective contacts, we explore the influence of a degraded selective contact on carrier collection by diffusion. Besides the well-known issue of surface recombination, we develop a new model in which carrier collection is reduced by a leakage at the contact, due to interfacial band gap states. This model shows that low-quality interfaces cause strong deviations from current-potential characteristics of the diode model, which relate to a significant reduction of the power output of the solar cell. (C) 2004 Elsevier B.V. All rights reserved.