produce single-crystal silicon. 1921 - Einstein awarded the Nobel Prize in Physics for his work on the photoelectric effect. 1930–1959 1932 - Audobert and Stora discover the photovoltaic effect in Cadmium selenide (CdSe), a photovoltaic material still used today. 1935 - Anthony H. Lamb receives patent US2000642, "Photoelectric device." 1941 - Russell Ohl files patent US2402662, "Light sensitive device." 1948 - Gordon Teal and John Little adapt the Czochralski method of crystal growth to produce single-crystalline germanium and, later, silicon. 1950s - Bell Labs produce solar cells for space activities. 1953 - Gerald Pearson begins research into lithium-silicon photovoltaic cells. 1954 - On April 25, 1954, Bell Labs announces the invention of the first practical silicon solar cell. Shortly afterwards, they are shown at the National Academy of Sciences Meeting. These cells have about 6% efficiency. The New York Times forecasts that solar cells will eventually lead to a source of "limitless energy of the sun". 1955 - Western Electric licences commercial solar cell technologies. Hoffman Electronics-Semiconductor Division creates a 2% efficient commercial solar cell for $25/cell or $1,785/watt. 1957 - AT&T assignors (Gerald L. Pearson, Daryl M. Chapin, and Calvin S. Fuller) receive patent US2780765, "Solar Energy Converting Apparatus." They refer to it as the "solar battery". Hoffman Electronics creates an 8% efficient solar cell. 1957 – Mohamed M. Atalla develops the process of silicon surface passivation by thermal oxidation at Bell Laboratories. The surface passivation process has since been critical to solar cell efficiency. 1958 - T. Mandelkorn, U.S. Signal Corps Laboratories, creates n-on-p silicon solar cells, which are more resistant to radiation damage and are better suited for space. Hoffman Electronics creates 9% efficient solar cells. Vanguard I, the first solar powered satellite, was launched with a 0.1 W, 100 cm2 solar panel. 1959 - Hoffman Electronics creates a 10% efficient commercial solar cell, and introduces the use of a grid contact, reducing the cell's resistance. 1960–1979 1960 - Hoffman Electronics creates a 14% efficient solar cell. 1961 - "Solar Energy in the Developing World" conference is held by the United Nations. 1962 - The Telstar communications satellite is powered by solar cells. 1963 - Sharp Corporation produces a viable photovoltaic module of silicon solar cells. 1964 - The satellite Nimbus I is equipped with Sun-tracking solar panels. 1964 - Farrington Daniels' landmark book, Direct Use of the Sun's Energy, published by Yale University Press. 1967 -