The influence of C-60 as a buffer layer on photovoltaic performance and stability of bulk heterojunction solar cells using a photoactive layer of CdTe nanocrystals and poly(p-phenylenevinylene) derivative has been investigated. The incident photon-to-current conversion efficiency of the sealed-cells with a C-60 buffer layer was about 70% of that of solar cells using a buffer layer of LiF. The introduction of C-60 buffer layer gave an improvement in the stability for a light-harvesting test. In a long-term thermal stability test, there was no difference between the solar cells using C-60 and LiF. An impedance analysis suggested that the degradation of the performance in the stability tests was associated with a decrease in the conductance of the cells. (c) 2005 Elsevier B.V. All rights reserved.