Solar-cell performance parameters calculated at baseline conditions (no grading) for thicknesses of . The dashed and dashed-dotted lines assume that the carrier lifetime varies with thickness. The symbols show experimental results (Refs. 2–4).
Solar-cell performance parameters of uniform band-gap absorber for thicknesses of , 0.5, and . Recombination at the interface, which can lead to a limitation of the open-circuit voltage (Ref. 18), is neglected.
parameters with varying thicknesses and absorber carrier concentrations. Thin devices tend to be fully depleted and their performance is independent of . From top left to bottom right: , FF (%), and (%).
parameters with varying thicknesses and minority carrier lifetimes. From top left to bottom right: , FF (%), and (%).
parameters with varying back-contact barrier. The performance of thick devices is independent of the back-barrier height. From top left to bottom right: , FF (%), and (%).
Three scenarios are considered for grading (Ga incorporation): (a) electron reflector, which reduces the back-contact recombination velocity; (b) half graded, which assumes that the incorporated Ga is somewhat diffused throughout half of the thickness; and (c) full graded, the Ga is diffused throughout the absorber.
Performance comparison of Fig. 6 grading profiles to ungraded absorber. Back optical reflection and .
Comparison of changes in performance parameters between abrupt (“electron reflector”) and diffused (“full graded”) Ga profile. The latter is less beneficial than a simple electron reflector. From top to bottom: (V), and (%).
Short-circuit current and efficiency vs absorber thickness (1.15 eV): At thickness the potential efficiency gain is 0.7%.
Variation of parameters due to fluctuations in material parameters: (a) thickness: (b) back contact: at ; (c) grading A: at ; and (d) grading B: at .
Article metrics loading...
Full text loading...