Abstract:
CuSCN is a highly stable, easy to fabricate, and efficient hole transport layer. It is
proposed to be a very stable alternative to its organic counterparts. The major research
problem with this layer is the degradation action of polar solvents (Diethyl sulfide &
Dipropyl sulfide) on the organic absorber layers. Researchers are using various
bilayers to overcome this issue. Here we have proposed a bilayer of CuSCN with a
different ammonia-based aqueous solvent. These bilayers exhibited better surface
roughness values of ( ̴ 26 nm) as compared to DES processed CuSCN layers that
inhibit roughness values of above (40 nm). These layers yielded smoother surfaces
that are suitable for perovskite absorber layer growth. Moreover, we observed a light
transmittance of up to 80% that can enable devices to harvest more especially from
the lower wavelengths. Hole mobility rates of up to (8.751x101) and bulk carrier
concentrations ranging between (1013 to 1015) /cm3 make them quite favorable for a
good transport layer. Contact angle studies for the proposed bilayers showed that these
layers still offer good hydrophobic properties up to (105⁰) while offering a better
surface for a healthy absorber layer grain size. Further investigation of surface
morphology shows that our proposed bilayers can function better on both Planar (n-ip)
and inverted planar (p-i-n) architectures. The successful demonstration of solutionprocessed CuSCN hole transport bilayers with perovskite absorber layer in
Photoluminescence analysis shows how beneficial these layers can be for the
fabrication of highly efficient and stable perovskite solar cells.
