14. The space charge limited current (SCLC) measurement
14
Nt = 2εεoVtfte-1d-2
Device Nt (cm-3
)
RP0 (a) 1.595 x 1016
RP1 (b) 1.500 x 1016
RP2 (c) 1.107 x 1016
RP3 (d) 1.329 x 1016
RCP25 (e) 1.440 x 1016
Trap-state density (Nt):
(Vtft: trap-filled limit voltage,
L: thickness of perovskite
film, ε: the relative dielectric
constant of perovskite, εo:
the vacuum permittivity)
15. Conclusion
Anatase TNPs/rutile TNRs heterostructures were successfully obtained by two-steps
hydrothermal process. P25 nanoparticles/ TNRs ETL was also prepared by a simple spin-
coating method.
Compared with pure rutile TNRs based PSCs, the devices based on TiO2 heterostructures
exhibited an improvement in performance.
The optimal ETLs was RP2, which contains TNPs prepared by the second hydrothermal
process with 0.066M TTIP. The champion PCE of the device based on this ETL was 14.143 %.
This remarkable performance is assigned to the improvement of carrier extraction
capability, the reduction of charge recombination, the light scattering phenomena, and the
passivation of trap states at the ETL/perovskite interface.
15
16. Future plan
Research on efficient spin-coating method for TiO2 nanorods-based perovskite solar cells with high
performance and uniformity
16
10 20 30 40 50 60 70 80 90
(116)
(220)
Intensity
(a.u.)
2q (degree)
TNR-PSK (DMF-IPA_2steps)
TNR-PSK (DMF-DMSO_1 step)
New method
(110)
(a)
(b)
(c)
MAI
PbI2
MA solution
in Ethanol +
Acetonitrile
Pre-heating at 70oC
Dynamic spin-coating
3000 rpm, 30 s