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It is widely known that the conversion efficiency and lifetime of solar cell modules decrease with higher operating temperatures. To maximize both efficiency and reliability, solar cell modules benefit greatly from the use of daytime passive radiative cooling techniques. In this study, we introduce a simple, low-cost, double-layer coating based on porous T i O 2 as a daytime passive radiative cooling system to achieve sub-ambient operating temperatures in a solar cell module. The top and bottom layers of the implemented design are porous T i O 2 and BK7 (glass), respectively. This solar cell/radiative cooling hybrid design is capable of achieving both high solar absorption in the photovoltaic conversion band 0.3–1.1 µm and high emissivity over 0.96 in the atmospheric transparency window 8–13 µm, while rejecting parasitic solar absorption. At 800 W / m 2 solar heating power, we found that adding the proposed cooling design on top of mono-crystalline silicon (m-Si), the solar cell panel lowered its operating temperature by 18.04°C, leading to a relative (effective) efficiency advantage of 21.56%. Additionally, at steady-state temperature (325 K), the power conversion efficiency of our radiative-cooler-coated m-Si solar cell is estimated to reach 20.46%, in contrast to 16.83% for an uncoated silicon solar cell. When compared with an uncoated silicon solar cell, optoelectronic simulations of our coated silicon solar cell show a short-circuit current density J s c as high as 5.07 m A / c m 2 , and the open circuit voltage V o c increased from 771.78 to 776.3 mV.

We use a combination of quenched molecular dynamics and embedded atom method to calculate the activation energy barriers for the hopping and exchange mechanisms of Au, Ag or Cu on Au(100), Ag(100) or Cu(100) stepped surfaces. Our findings show that the Ehrlich–Schwöbel (ES) barriers for an adatom to undergo jump or exchange at a step edge are found to be dependent of the nature of substrate stepped surfaces. We also find that the ES barriers for the hopping processes are too high, except for Cu/Au(100). While for exchange process the Ehrlich–Schwöbel barriers are found to be very low and even negative. These ES barriers can explain the difference in the growth modes for the different systems. On the other hand, we calculated the adsorption energies at the most stable adsorption sites near step edges. In particular, we wish to clarify the relation between the adatom diffusion energy barriers and the adatom adsorption energies. These results may serve as some guiding rules for studying stepped surface morphologies, which are of importance to surface nanoengineering.