Snaith group

Abstract:

Upon the addition of lithium salts to the hole-transporter matrix, 2, 2′, 7, 7′ -tetrakis (N,N -di- p -methoxypheny-amine)- 9, 9′ -spirobifluorene (spiro-MeOTAD), the authors observe a 100-fold increase in conductivity through spiro-MeOTAD within a Ti O2 mesoporous network. The authors demonstrate this to be a bulk effect and not due to improved injection at the electrodes. By testing "hole-only" diodes of pure spiro-MeOTAD and those doped with lithium salts, the authors calculate that the hole mobility increases from 1.6× 10-4 to 1.6× 10-3 cm2 V s. The authors discuss the possible mechanisms for this significant enhancement in charge mobility and its implication to the dye-sensitized solar cell operation. © 2006 American Institute of Physics.

Abstract:

We present the first application of an amorphous "liquid" organic semiconductor in an optoelectronic device, demonstrating that it is highly suited for use as a hole-transporting material in nanostructured dye-sensitized solar cells. For such devices, we obtain power conversion efficiencies of up to 2.4% under simulated air mass 1.5 solar spectrum at 100 mWcm(-2), and incident photon-to-electron quantum efficiencies in excess of 50%.