The annual Tech Awards, whose primary sponsor is Applied Materials working in conjunction with Santa Clara University's Center for Science, Technology and Society, invited 12 global social entrepreneurs chosen from hundreds of nominees to spend a week in Silicon Valley to celebrate their work and help them hone business plans and network with potential partners and funders. The six top winners were awarded cash prizes of $75,000 each, while the other six received $25,000 each.

Here are the six top awards and their winners:

Accenture Sustainable Energy Award: Simpa Networks, which created a pay-as-you-go pricing mobile payment system that enables people in India and elsewhere to access affordable solar energy. Website: Simpanetworks.com

Flextronics Economic Development Award: Pamela C. Ronald, David Mackill and Kenong Xu, who developed a rice gene that allows farmers in flood-prone regions to grow crops that can endure flooding. Website: http://indica.ucdavis.edu

Intel Environment Award: Arup K. SenGupta, whose foundation provides easy-to-use technology to eliminate arsenic poisoning from water in Cambodia, Nepal, India, Bangladesh and Vietnam. Website: thetsfoundation.org

Microsoft Education Award: Literacy Bridge Talking Books, which provides a durable battery-operated audio computer in Africa to play locally produced lessons in agriculture and basic health to the poor who often lack electricity and are illiterate. Website: www.literacybridge.org

Nokia Health Award: The BioLite HomeStove, which is a low-cost, highly efficient wood-burning stove that dramatically reduces smoke and harmful black carbon emissions while reducing fuel needs by 50 percent. Website: www.biolitestove.com

Katherine M. Swanson Young Innovator Award: Angaza Design, which developed a low-cost, pay-as-you go technology integrated with local mobile money platforms that allows the poor in Tanzania, Kenya and Zambia to buy electricity with small amounts of cash on hand. Website: www.angazadesign.com