geminate recombination and non-geminate recombination in organic solar cells
有机太阳能电池中的孪生复合与非孪生复合
Below content was copied fromAdv. Funct. Mater. 2013,DOI: 10.1002/adfm.201202643
"Nongeminate Recombination and Charge Transport Limitations in Diketopyrrolopyrrole-Based Solution- Processed Small Molecule Solar Cells"
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Geminate recombination occurs when a coulombically bound electron-hole pair generated from absorption of a single photon recombines before the electron and hole can separate into free charge carriers. Nongeminate recombination is the recombination of free charge carriers and encompasses both trap-assisted and bimolecular mechanisms. Experimentally, geminate and nongeminate mechanisms can be distinguished by observing the timescale at which they occur and their dependence on carrier density. The probability of geminate recombination is independent of carrier density and geminate losses happen within
nanoseconds of absorption. In contrast, nongeminate losses are carrier density dependent and typically occur after micro-to milliseconds when illumination conditions are comparable to 1 sun.