(ShareCast News) - Nanoco Group chairman Christopher Richards on Monday dipped into the market for the second time in a week as he picked up shares in the supplier of quantum dots for flatscreen televisions and other screen markets.Richards, former chief executive of agrochemical business Arysta who was appointed in May, bought 19,833 shares in the AIM-listed company at a price of 50.42p, following the purchase of 55,576 at 53.98p last week, to total almost £40,000.Fellow non-executive Gordon Hall also bought 18,230 shares last week at a price of 54.39p.Directors were not the only ones dealing, as institutional investor Baillie Gifford sold down its stake below 10%, it was also revealed on Monday, fromNanoco shares nevertheless sank back below 50p for the first time since the end of June after losing plenty of ground from August's one-year high above 76p as preliminary results earlier this month disappointed investors.The maker of cadmium-free quantum dots refined its business model in May, so upfront licence fees associated with the agreements are to be recognised over the period of Nanoco's contractual support.While the group has since signed non-exclusive deals with Taiwan-headquartered Wah Hong Industrial Corporation and Germany's Merck, and revised its deal with Dow Chemical, but this meant that revenues in the year to 31 July were not as high as many investors might have expected.At the release of results last week Richards said he was encouraged that the significant progress made during the year, especially in new licensing agreements and manufacturing improvements, has "put the group in a strong position for rapid revenue growth. Combined with our solid cash position, we look forward to the future with confidence." Top Director BuysTungsten Corporation (TUNG)Director name: Williams,DavidAmount purchased: 25,000 @ 60.28pValue: £15,071.03Tungsten Corporation (TUNG)Director name: Williams,DavidAmount purchased: 25,000 @ 59.74pValue: £14,935.62Tungsten Corporation (TUNG)Director name: Williams,DavidAmount purchased: 25,000 @ 59.50pValue: £14,875.00Tungsten Corporation (TUNG)Director name: Williams,DavidAmount purchased: 25,000 @ 59.44pValue: £14,859.38Energiser Investments (ENGI)Director name: Malde,Nishith Motilal MeghjiAmount purchased: 20,000 @ 2.25pValue: £450.00Saga (SAGA)Director name: Batchelor,LanceAmount purchased: 73 @ 203.90pValue: £148.85 (BIH)Director name: James,William BordenAmount purchased: 1 @ 100.00pValue: £1.00Top Director SellsRicardo (RCDO)Director name: Shemmans,DaveAmount sold: 36,613 @ 1,010.00pValue: £369,791.31Ricardo (RCDO)Director name: Garrett,MarkAmount sold: 7,838 @ 1,010.00pValue: £79,163.80