Configuration of the p-n t-ssDSCs, energy alignment of each component, and the individual p-ssDSC and n-ssDSC are depictured in Figure and. On the basis of our previous work on p-ssDSCs, we used a compact NiO layer on FTO glass to avoid short circuit with the back contact onto which a PB6-sensitized mesoporous NiO layer was deposited, as shown in with "normal" ALD. To protect the film from short-circuits caused by the sputtering of ITO back contact, we added an extra layer of spin-coated Zn(acac)2 layer that was transformed to ZnO upon heat exposure to 200 °C. We found that the combination of ZnO from ALD with the extra layers from Zn(acac)2 solution yielded the best performing cells (SI, Figure ). This is likely due to a combination of a good pore filling from the ALD with the extra protection of the additional ZnO layer during the consequent sputtering process. Aging was also found to be an important part to get good working cells, and storage in the dark in ambient air improved cell performance significantly (SI, Figure ), corresponding with previous literature. The n-ssDSC was fabricated from a D35-sensitized mesoporous TiO2 layer on a compact TiO2 blocking layer (Figure ). The hole-transporting material (HTM), a lithium doped Spiro-OMeTAD solution (SPIRO), was spin-coated on the dye-sensitized film. The transparent ITO back contact was then directly deposited on the HTM. To assemble the p-n tandem cell, the p-ssDSC cell was placed on the top due to its lower photocurrent compared to the n-ssDSCs. Even the current published record photocurrent for p-ssDSCs, with a short-circuit photocurrent density (Jsc) of 1 mA/cm 2 , is still considerably lower than for n-ssDSCs. The t-ssDSCs is therefore illuminated from p-type side since the overall photocurrent is limited by the cell with the lowest current in a series connection, which limits the overall performance in our case (Figure ). We additionally adjusted the thickness of the TiO2 in the n-ssDSC to match the photocurrent when shaded by the p-ssDSC on top to suppress unnecessary photo annihilation (SI, Figure , S4). Two layers of the spin-coated meso-TiO2 solution proved to be ideal to match the Jsc of the p-ssDSC of around 0.8 mA/cm 2 .