Which 1954 device is widely recognized as the first practical silicon solar cell?

The Bell Labs silicon solar cell, demonstrated in 1954, is widely recognized as the first practical silicon solar cell.

Researchers Daryl Chapin, Calvin Fuller, and Gerald Pearson developed the device at Bell Telephone Laboratories in the United States. Their cell used silicon treated with impurities to create a junction that separated charge carriers generated by sunlight. It achieved an efficiency of about 6 percent, a major improvement over earlier selenium-based cells.

Earlier experiments had already shown that light could produce electricity. Charles Fritts built an early selenium cell in the nineteenth century, but its performance was too low for widespread power generation. Bell Labs’ silicon device was practical enough to attract attention for remote electrical equipment and space applications.

The technology soon became important for satellites, where sunlight offered a reliable power source without fuel deliveries. Modern solar modules use more advanced cell designs and achieve much higher efficiencies, but they retain the basic photovoltaic principle demonstrated by the Bell Labs team.