Study On Mesoporous Perovskite Solar Cell Based On Composite Hole Transporting Material

Humanity is facing two big issues, One is energy crisis and the other is environmental pollution. Therefore, to develop clean energy is the future current. Solar energy is considered the most promising clean energy, because of its rich resources, widespread. The solar cells is an effective way to convert solar energy into electrical energy.Because the advantage of longer charge diffusion length, high light absorption coefficient, suitable bang gap, The materials of Organic-inorganic halide lead perovskite received Widespread concern. Recent years, Based perovskite material, The photoelectric conversion efficiency of solar cells rapidly increase. From 3.8%to 20%. Hole-transporting material(HTM) is an important component of the perovskite solar cell, Its role is to transport holes to the electrode and hinder electronic. Its ability of spread holes is the key factor to determine the photoelectric conversion efficiency of perovskite solar cells. Spiro-OMeTAD is commonly used as hole transporting material of perovskite solar cells, Because it has appropriate bandgap. However, it also has many disadvantages. Such as the carrier mobility is low, poor stability, synthesis process complexity and high cost. So to find out a hole transport material which has high carrier mobility, more stability, and suitable to solution method is significance. CuO and CuO2 as very stable structure of copper oxide comply with the above requirements. It has simple preparation technology and high carrier mobility. This paper use copper oxide and Spiro-OMeTAD to prepare composite hole transport layer. Details are as follows:This paper use Titanium dioxide as electron transporting material and skeleton layer, CH3NH3PbI3 as light-absorbing material, Spiro-OMeTAD as hole transporting material, gold as an electrode. To make perovskite solar cells with the structure of FTO/compact TiO2 layer/Mesoporous TiO2 layer/CH3NH3PbI3 layer /Spiro-MeoTAD/Au. By optimizing the process conditions, such as the preparation process of PbI2 and the concentration of CH3NH3I, Obtaining the mesoporous perovskite solar cell with a photoelectric conversion efficiency of more than 11%.Based on this, Introducing a new layer of the hole transport material by solution method, which is CuOx, placing it between CH3NH3PbI3 layer and Spiro-OMeTAD, consititue a new composite hole transport layer with Spiro-OMeTAD. Battery test results confirmed that this new composite hole transport solar cell has higher photoelectric conversion efficiency(From 10.94% to 12.3%), and higher short circuit current(From 18.2 mA/cm2 to 19.5 mA/cm2), compared with the solar cell without CuOx. Found by SEM and AFM, the modification of CuOx layer can effectively decrease the roughness of CH3NH3Pbl3. Moreover, the result of fluorescence testing show that CuOx layer play a positive role in reducing the light-generated carriers complex and effective extraction hole.