App note from Vishay demonstrating a circuit to power IoT sensors with energy storage capacitors. Link here (PDF)
The V-harvester board is a photovoltaic (PV) harvesting backup demonstration circuit. It is a sophisticated stand-alone board charged using TEMD5080X01 micro PV cells or with micro USB. The input power goes into an e-peas low power AEM10941 controller, where it is stepped up to the supercapacitor voltage of 4.2 V. Upon power demands at the interface or ENLV, ENHV settings, the controller converts the supply voltage to the target voltages using low dropout regulators (LDO).