Organic-inorganic hybrid materials can promise both the superior carrier mobility of inorganic semiconductors and the processability of organic materials. Perovskite alkyl ammonium lead halides have the strong potential to serve as the ultra-high efficient solar sensitizer for next-generation solar cells. Also (CH3NH3)PbI3 has similar band gap of silicon, thus it is attracting huge attention for various applications. In this study, we report that nonlinear current (I-V) characteristics of (CH3NH3)PbI3. We find that electrical properties of (CH3NH3)PbI3 strongly depend on how this material being prepared. Since electrical properties of polycrystalline(CH3NH3)PbI3 films synthesized with solution process largely vary with the grain size, it is difficult to examine the intrinsic properties of (CH3NH3)PbI3. To solve this, we used a thermal evaporator to get(CH3NH3)PbI3 films with precise thicknesses and reproducible crystallinity. Our experimental results reveal that I-V characteristics of (CH3NH3)PbI3 films are very nonlinear. I-V curves are Ohmic-like linear in low bias voltages, but current increases rapidly in medium bias voltages. For the higher voltages, the films show saturation in current. From these nonlinear I-V characteristics, it is possible to analyze conduction mechanism in (CH3NH3)PbI3 films. We reveal that the bias-dependent current flow originates from interplay between space-charge limited and trap-charge limited conductions. It is suggested that the control of trap-assistant current flow is a key for developing for solar cells with even higher efficiencies and high performance transistors based on perovskite alkyl ammonium lead halides.

Nonlinear current-voltage characteristics of perovskite alkyl ammonium lead halides

248th National Meeting (2014)

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