The present invention provides a porous semiconductor electrode passivated by way of a layer applied by an atomic layer deposition (ALD) process. The semiconductor electrode can be advantageously used in dye-sensitized solar cells (DSCs) having increase open current voltages (Voc). By selecting the thickness and the material of the passivating or blocking layer, high Voc without substantial reduction of short circuit current (JSC) is achieved, thereby resulting in devices exhibiting excellent power conversion efficiencies.