The electronic and materials properties of two series of wide-bandgap solar cells with Cu-poor CuGaSe2 (CGS) absorbers have been studied, to better understand limitations on the device performance. One series of samples displayed distinct lateral non-uniformities in Cu/Ga ratio, Na content, and thickness, likely due to a limited supply of Se during CGS growth. The second series of samples appeared uniform. The most prominent electronic difference was the presence of a distinct band of near-interface defect states in the more non-uniform set of samples. The device performance did not appear to be limited by defects in the bulk CGS film until the defect density was larger than 2×1016 cm-3. Instead, interface recombination appears to be a significant factor limiting Voc in both sets of samples.