Free-space optical communication holds the promise of high-throughput wireless communication channels for long distances as well as for short-range indoor applications. To fully benefit from the high data rates enabled by optical carriers, the light needs to be efficiently collected onto a fast photodetector, which requires complex pointing and tracking systems. Here, we show that fluorescent materials can be used to increase the active area of a photodiode by orders of magnitude while maintaining its short response time and increasing its field of view. Using commercially available materials,we demonstrate a detector with an active area of 126 cm2 achieving data rate sup to 2.1 Gbps at an eye-safe intensity. We demonstrate a detector geometry with omnidirectional sensitivity and discuss the need for new materials tailored for communication applications.