Defective TiO2 with high photoconductive gain for efficient and stable planar heterojunction perovskite solar cells

Li, Y. et al. Defective TiO2 with high photoconductive gain for efficient and stable planar heterojunction perovskite solar cells. Nature Communications, 7, 12446, DOI: 10.1038/ncomms12446 (2016).

Defects in TiO2 electron selective contacts to halide perovskite light absorbers are engineered to beneficially reduce photocatalytic degradation and enable a high photoconductive gain.

Long-term stability and high efficiency from planar heterojunction halide perovskites is enabled by addressing interfacial degradation and charge transfer resistance limitations.

Photovoltaic device structure used for evaluating impacts of defect-engineered TiO2 in interfacial processes. Reprinted from Li, Y. et al. Defective TiO2 with high photoconductive gain for efficient and stable planar heterojunction perovskite solar cells. Nature Communications, 7, 12446, DOI: 10.1038/ncomms12446 (2016).

Photovoltaic device structure used for evaluating impacts of defect-engineered TiO2 in interfacial processes. Reprinted from Li, Y. et al. Defective TiO2 with high photoconductive gain for efficient and stable planar heterojunction perovskite solar cells. Nature Communications, 7, 12446, DOI: 10.1038/ncomms12446 (2016).

(a) JV curves of one of the highest-performing devices measured in the forward and reverse scan directions at a rate of 10 mV per step under 100 mW cm−2 AM 1.5G illumination. (b) EQE spectrum of the solar cell measured at the short-circuit condition (orange squares). The integration of the EQE spectrum with the AM 1.5G photon flux is also shown (blue line) and agrees to within 1% of the short circuit current density obtained from JV measurements. (c) Steady-state measurement of the photocurrent near the maximum power point at 0.85 V. (d) JV curves of the same device measured with different step delay times and (e) voltage step sizes. All the above measurements were carried out after light soaking for ~20 min. Reprinted from Li, Y. et al. Defective TiO2 with high photoconductive gain for efficient and stable planar heterojunction perovskite solar cells. Nature Communications, 7, 12446, DOI: 10.1038/ncomms12446 (2016).

(a) JV curves of one of the highest-performing devices measured in the forward and reverse scan directions at a rate of 10 mV per step under 100 mW cm−2 AM 1.5G illumination. (b) EQE spectrum of the solar cell measured at the short-circuit condition (orange squares). The integration of the EQE spectrum with the AM 1.5G photon flux is also shown (blue line) and agrees to within 1% of the short circuit current density obtained from JV measurements. (c) Steady-state measurement of the photocurrent near the maximum power point at 0.85 V. (d) JV curves of the same device measured with different step delay times and (e) voltage step sizes. All the above measurements were carried out after light soaking for ~20 min. Reprinted from Li, Y. et al. Defective TiO2 with high photoconductive gain for efficient and stable planar heterojunction perovskite solar cells. Nature Communications, 7, 12446, DOI: 10.1038/ncomms12446 (2016).

Research Details:

JCAP 10.1038/ncomms12446
  • Hole-trapping states introduced to TiO2 via low temperature deposition in an oxygen-deficient atmosphere
  • Hole trapping reduces interfacial photocatalytic oxidation of perovskite and allows high photoconductive gain that improves electron extraction efficiency

Contact:  idsharp@lbl.gov and fmtoma@lbl.gov

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