A one-watt solar power plant

Shortly after the announcement1 of the invention of the Bell Solar Battery, Bell Telephone Laboratories undertook an exploratory development program with a twofold purpose. First, device designers wanted to learn how to make large quantities of silicon photodiodes, how to devise reliable connections to the active parts of the diode, and if possible, how to increase the realizable efficiency of conversion of sunlight to electricity. Second, system designers wished to find out how to use the new photodiodes in the most efficient and practical way in power plants for telephone equipment.