Here is a project of a solar powered AM radio receiver circuit. The circuit is built around a MK484 AM radio IC. MK484 IC is a good quality am receiver IC comes in TO92 transistor package requires only few external components because all the necessary circuitry like RF detector, AGC, RF amplifier are
incorporated inside the IC. The voltage source of this radio circuit is a 1.5 volt solar cell but you can also use a 1.5 volt battery in the place of solar cell if desired. The two 9014 transistors are used to amplify the audio output of the IC. The Coil L1 is equal to 55 turns of 0.315mm (30 swg) enameled copper wire wound on 10mm x 100mm long ferrite rod. You can also use any similar ICs like YS414 and TA7642 in the place of MK484. The sensitivity and selectivity can be further increased with the help of AM loop antenna.