A hole conductor-free mesoscopic CH3NH3PbI3/TiO2 heterojunction solar cell has been developed. The perovskite nanoparticles, synthesized from a solution of CH3NH3I and PbI2 in γ-butyrolactone, are deposited on a 400 nm thick TiO2 nanosheet film with (ooi) facets. The CH3NH3PbI3 nanoparticles act as both light harvesters and hole conductors, eliminating the need for an additional hole transport material. The solar cell achieved a short circuit current (Jsc) of 16.1 mA/cm², an open circuit voltage (Voc) of 0.631 V, and a fill factor (FF) of 0.57, corresponding to a power conversion efficiency (PCE) of 5.5% under standard AM 1.5 solar light. At a lower light intensity of 100 W/m², a PCE of 7.3% was measured. The device shows excellent performance with an incident photon-to-current efficiency (IPCE) of up to 90% in the 400-540 nm range. The perovskite is stable in dry ambient air and can be deposited by low-cost solution processing, making it suitable for future high-efficiency, low-cost photovoltaic cells. The TiO2 nanosheets serve as electron collectors, while the CH3NH3PbI3 acts as the light absorber and hole conductor. The solar cell fabrication involves spin coating of the perovskite precursor solution on the TiO2 film, followed by annealing and gold contact deposition. The device's performance was characterized using a solar simulator and monochromatic light sources, demonstrating its potential for further improvements in PCE through enhanced FF and Voc.A hole conductor-free mesoscopic CH3NH3PbI3/TiO2 heterojunction solar cell has been developed. The perovskite nanoparticles, synthesized from a solution of CH3NH3I and PbI2 in γ-butyrolactone, are deposited on a 400 nm thick TiO2 nanosheet film with (ooi) facets. The CH3NH3PbI3 nanoparticles act as both light harvesters and hole conductors, eliminating the need for an additional hole transport material. The solar cell achieved a short circuit current (Jsc) of 16.1 mA/cm², an open circuit voltage (Voc) of 0.631 V, and a fill factor (FF) of 0.57, corresponding to a power conversion efficiency (PCE) of 5.5% under standard AM 1.5 solar light. At a lower light intensity of 100 W/m², a PCE of 7.3% was measured. The device shows excellent performance with an incident photon-to-current efficiency (IPCE) of up to 90% in the 400-540 nm range. The perovskite is stable in dry ambient air and can be deposited by low-cost solution processing, making it suitable for future high-efficiency, low-cost photovoltaic cells. The TiO2 nanosheets serve as electron collectors, while the CH3NH3PbI3 acts as the light absorber and hole conductor. The solar cell fabrication involves spin coating of the perovskite precursor solution on the TiO2 film, followed by annealing and gold contact deposition. The device's performance was characterized using a solar simulator and monochromatic light sources, demonstrating its potential for further improvements in PCE through enhanced FF and Voc.